Sweating Disorders

PURPOSE OF REVIEW

This article reviews disorders of sweating, including hyperhidrosis and anhidrosis due to central or peripheral autonomic nervous system causes.

RECENT FINDINGS

Disorders of thermoregulation and sweating may manifest with hyperhidrosis or hypohidrosis/anhidrosis. Primary disorders of hyperhidrosis may significantly impact quality of life yet tend to be benign. Many sweating disorders present with compensatory hyperhidrosis due to areas of anhidrosis. Anhidrosis may occur due to either central or peripheral damage to the autonomic nervous system. The thermoregulatory control of sweating involves central pathways from the hypothalamus to the brainstem and then spinal cord as well as projections to peripheral structures, including the sympathetic chain ganglia, peripheral nerves, and eccrine sweat glands. Disruption at any point of this pathway may lead to impaired sweating. Characterization of sweating dysfunction helps localize different autonomic disorders to guide diagnosis and may allow for evaluation of treatment effect.

SUMMARY

Sweating dysfunction manifests in myriad ways, including essential hyperhidrosis, complete anhidrosis with heat intolerance, and compensatory hyperhidrosis due to anhidrosis, and often indicates involvement of underlying central or peripheral autonomic dysfunction.

Histamine Modulates Sweating and Affects Clinical Manifestations of Atopic Dermatitis

Many factors such as food or environmental allergens, bacteria, fungi, and mental stress aggravate the condition of atopic dermatitis (AD) eczema. Sweating can also exacerbate AD, and patients are aware of that. In the past, it has been reported that contamination of skin surface antigens by sweat induces acute allergic reactions and that sweating functions of AD patients via axonal reflexes are decreased. Histamine demonstrably inhibits acetylcholine-induced sweating in both mice and humans via histamine H1 receptor-mediated signaling. In sweat glands, acetylcholine inactivates glycogen synthase kinase 3β (GSK3β), a kinase involved in endocytosis and secretion, whereas simultaneous stimulation with histamine activates GSK3β and inhibits sweat secretion. Thus, histamine might be involved in the mechanism of abnormal skin dryness in patients with AD via decreasing sweat secretion. On another front, some patients secrete sweat normally. Patients with regular sweating are prone to develop skin disorders such as papules or erythema by residual sweat left on the skin surface. Patients with decreased sweating are prone to develop disorders characterized by xerosis, lichenoid changes, prurigo by elevated skin temperature, skin dryness, and compromised skin conditions. Careful inspection of skin manifestations provides a good indication of a patient's ability to sweat.

New Etiology of Cholinergic Urticaria

Cholinergic urticaria (CholU) is characterized by pinpoint-sized, highly pruritic wheals occurring upon sweating. Both direct and indirect theories in the interaction of acetylcholine (ACh) with mast cells have been put forward in the sweating-associated histamine release from mast cells. In the mechanism of indirect involvement of ACh, patients are hypersensitive to sweat antigen(s) and develop wheals in response to sweat substances leaking from the syringeal ducts to the dermis, possibly by obstruction of the ducts. Some patients with CholU exhibit a positive reaction to intradermal injection of their own diluted sweat, representing 'sweat allergy (hypersensitivity)'. Regarding the direct interaction theory between ACh and mast cells, we found that CholU with anhidrosis and hypohidrosis lacks cholinergic receptor M3 (CHRM3) expression in eccrine sweat gland epithelial cells. The expression of CHRM3 is completely absent in the anhidrotic areas and lowly expressed in the hypohidrotic areas. In the hypohidrotic area, where CholU occurs, it is hypothesized that ACh released from nerves cannot be completely trapped by cholinergic receptors of eccrine glands and overflows to the adjacent mast cells, leading to wheals.

Sweating impairment in patients with multiple sclerosis

OBJECTIVES

To measure sweating in patients with multiple sclerosis (MS).

MATERIALS AND METHODS

Sweating was measured by an evaporimeter after a heating stimulus in 29 MS patients and in 15 healthy control subjects.

RESULTS

The MS patients sweated markedly less than the controls. After 10 min of heating the sweating was significantly lower in the forehead (P = 0.034), feet (right, P = 0.033; left, P = 0.037) and legs (right, P = 0.043; left, P = 0.029) of the MS patients than in those of the controls. After 15 min of heating the difference was statistically significant only in the feet (right, P = 0.043; left, P = 0.029). The Expanded Disability Status Scale score correlated inversely with sweating at 15 min of heating in the left hand (r = 0.42, P < 0.05), and in the left (r = 0.36, P < 0.05) and right foot (r = 0.37, P < 0.05).

CONCLUSIONS

MS is associated with an impairment in thermoregulatory sweating which seems to be related to the disease severity.

Clinical laboratory evaluation of autoimmune autonomic ganglionopathy: Preliminary observations

Several forms of chronic autonomic failure manifest as neurogenic orthostatic hypotension, including autoimmune autonomic ganglionopathy (AAG) and pure autonomic failure (PAF). AAG and PAF are thought to differ in pathogenesis, AAG reflecting decreased ganglionic neurotransmission due to circulating antibodies to the neuronal nicotinic receptor and PAF being a Lewy body disease with prominent loss of sympathetic noradrenergic nerves. AAG therefore would be expected to differ from PAF in terms of clinical laboratory findings indicating post-ganglionic noradrenergic denervation. Both diseases are rare. Here we report preliminary observations about clinical physiologic, neuropharmacologic, neurochemical, and neuroimaging data that seem to fit with the hypothesized pathogenetic difference between AAG and PAF. Patients with either condition have evidence of baroreflex-sympathoneural and baroreflex-cardiovagal failure. Both disorders feature low plasma levels of catecholamines during supine rest, but plasma levels of the other endogenous catechols, dihydroxyphenylalanine (DOPA), dihydroxyphenylacetic acid (DOPAC), and dihydroxyphenylglycol (DHPG), seem to be lower in PAF than in AAG, probably reflecting decreased norepinephrine synthesis and turnover in PAF, due to diffuse sympathetic noradrenergic denervation. PAF entails cardiac sympathetic denervation, whereas cardiac sympathetic neuroimaging by thoracic 6-[(18)F]fluorodopamine scanning indicates intact myocardial sympathetic innervation in AAG.

Head and neck manifestations and quality of life of patients with ectodermal dysplasia

OBJECTIVES

Ectodermal dysplasias (EDs) are a group of genetic disorders characterized by deficient ectodermal and mesodermal development. Studies examining resultant otolaryngologic issues are few. The objectives of this study were to delineate the head and neck manifestations and quality of life in EDs.

STUDY DESIGN AND SETTING

For 75 individuals, comprehensive histories were taken and otolaryngologic examinations were performed, and subjects rated their otolaryngologic symptom severity. A validated quality of life instrument (SF-8) was administered.

RESULTS

The majority of subjects had a diagnosis of hypohidrotic ED (72%). Otolaryngologic conditions included otitis media (28%), cerumen impaction (48%), nasal obstruction/crusting (51%), heat intolerance (76%), and eczema (39%). Physical findings included peg teeth/hypodontia (76%), alopecia (41%), nasal crusting (41%), and saddle nose deformity (44%). Quality of life scores were generally high. Overall, health was rated "good to excellent" by 87 percent.

CONCLUSION

Patients with ED frequently experience significant otolaryngologic symptoms, although most patients report a good quality of life.

SIGNIFICANCE

A greater understanding of the otolaryngologic issues in ED should help facilitate diagnosis and improve management.

A preliminary study of the short circuit current (Isc) responses of sweat gland cells from normal and anhidrotic horses to purinergic and adrenergic agonists

The causal factors of equine anhidrosis have not yet been elucidated but defective electrolyte transport mechanisms in the gland are likely to be involved. To investigate this possibility, experiments were performed on cultured equine sweat gland epithelia from five free-sweating UK horses (3 intact males, 2 mares, aged 2-4 years) and from three free-sweating Singapore horses (1 intact male, 2 mares, aged 3-5 years) and three anhidrotic (Singapore) horses (1 intact male, 1 gelding, 1 mare, aged 3-6 years). Cultured cells from each animal were grown on permeable supports and loaded into Ussing chambers to quantify transepithelial resistance and agonist-induced electrolyte transport by the short circuit current (Isc) technique. Transepithelial resistances across the layers of cultured cells were not significantly different between cells from UK and Singapore free-sweating horses, but were significantly reduced in anhidrotic animals. Purinergic agonists added to the apical and basolateral aspects of the cultured cells caused similar increases in Isc between the two populations of unaffected cells, but Isc increases were significantly reduced in anhidrotic animals. Beta-adrenergic agonist stimulation of the anhidrotic cell layers failed to elicit any change in Isc. These pilot results not only confirm earlier conclusions from anatomical findings that failure in the secretory process occurs in anhidrosis but also indicate that both of the known ion transport mechanisms are involved. The trigger for these failures warrants further investigation.

Equine sweating and anhidrosis Part 2: anhidrosis

The condition of anhidrosis is described in this review, and the latest theories on the causal factors are explored. The evidence supports the hypothesis that anhidrosis is an inappropriate response to prolonged climatic stress (generally combined heat and high humidity), which can be evoked in a small (approximately 10 +/- 5%) proportion of the equine population. It is caused by gradual failure of the glandular secretory cell processes, initiated by desensitization and subsequent down-regulation of the cell receptors as a result of continued adrenaline-driven hyperactivity. It progresses through secretory failure and culminates in gradual, probably irreversible, glandular dedifferentiation and ultimate degeneration. There is a need for considerably more research on the secretory and transcriptional processes to document the changes arising within the glandular secretory mechanism as a prelude to development of a corrective treatment.

Anatomical redistribution of sweating after T2–T3 thoracoscopic sympathicolysis: a study of 210 patients

BACKGROUND

The cutaneous influence areas of the different sympathetic ganglia have not been fully established to date. The aim of this study was to define the cutaneous influence area of sympathetic ganglia T2-T3.

METHODS

A total of 210 patients with primary hyperhidrosis (PH) underwent 420 thoracoscopic sympathicolysis procedures of ganglia T2-T3 in a prospective study. All completed a preoperative questionnaire and a second questionnaire 12 months after the operation. The questionnaires evaluated perspiration in the different body areas. Only the zones of anhidrosis were considered in delimiting the cutaneous expression of sympathetic ganglia T2-T3.

RESULTS

Redistribution of perspiration as reported by the patients comprised significant reduction in the palms, axillas, and soles, and an increase in the abdomen, back, and gluteal and popliteal regions. Regarding the incidence of anhidrosis by anatomical location, statistically significant changes were recorded in the head, hands, axillas, and soles (p < 0.001).

CONCLUSIONS

Bilateral upper thoracic sympathicolysis is followed by redistribution of body perspiration, with a clear decrease in the zones regulated by mental or emotional stimuli, and an increase in the areas regulated by environmental stimuli, though we are unable to establish the etiology of this redistribution.

Equine sweating and anhidrosis Part 1 ? equine sweating

Sweating has a variety of functions in mammals including pheromone action, excretion of waste products and maintenance of the skin surface ecosystem. In a small number of mammalian species, which includes humans and the Equidae, it also has an important role in thermoregulation. This review is focused specifically on the thermoregulatory role of sweat in Equidae and the causes of sweating failure (anhidrosis). The first part describes the glandular appearance, sweat composition, and output rates; and considers the latest theories on the glandular control and secretory mechanisms. It is concluded that the glands are not directly innervated but are controlled by the interplay of neural, humoral and paracrine factors. The secretory mechanism is not as simple as previously thought and is mediated by the dynamic interaction of activating pathways, including autocrine control not only of the secretory process but probably also of secretory cell reproduction, growth, and death.

Ross syndrome: a rare or a misknown disorder of thermoregulation? A skin innervation study on 12 subjects

Ross syndrome is described as a rare disorder of sweating associated with areflexia and tonic pupil. Since Ross's first description in 1958, approximately 40 cases have been described. We assessed the involvement of cutaneous innervation in 12 subjects with Ross syndrome using quantitative sensory testing, sweating assessment and immunohistochemical study of anhidrotic and hyperhidrotic skin. This evaluation was repeated over time in 4 out of 12 subjects. In addition, we enrolled four subjects with Holmes-Adie syndrome (areflexia and tonic pupil) to investigate similarities between the two conditions. We found in Ross patients a complex and progressive involvement of cutaneous sensory and autonomic innervation underlying the impairment of heat production and heat dissipation through both loss of sweating and loss of cutaneous blood flow regulation. In Holmes-Adie subjects we found a mild impairment of sweating without thermoregulatory problems. The persistence of a sudomotor vasoactive intestinal peptide-immunoreactive (VIP-ir) innervation, although deranged and poor, definitely differentiated Holmes-Adie from Ross patients. Ross syndrome is a progressive and complex disorder of thermoregulation difficult to differentiate from the probably pathogenetically related Holmes-Adie syndrome. Sweating assessment and skin biopsy are suitable tools to define a boundary between them. Owing to the large number of Ross patients observed in only 5 years, and to the long and complex medical history of most of them, doubts arise on the effective rarity of this condition, and we warn family doctors and other specialists, besides neurologists, to become aware of this complex disorder.

QSART in idiopathic pure sudomotor failure

QSART (quantitative sudomotor axon reflex testing) was performed in a patient with idiopathic pure sudomotor failure. Generalized reduction in thermoregulatory sweating and complete absence of axon reflex sweating were observed, suggesting a deficit of sweat gland cholinergic synaptic transmission or receptors. QSART responded promptly to treatment. Putative pathophysiological mechanisms are discussed.

Ross syndrome, an entity included within the spectrum of partial disautonomic syndromes

Ross syndrome is a degenerative peripheral nervous system disorder defined by the following triad: unilateral or bilateral segmental anhidrosis, hyporeflexia of deep tendon reflexes and Adie's tonic pupils. The most disturbing symptom is segmental compensatory hyperhidrosis. It has only occasionally been reported in the dermatological literature. We present a 35-year-old woman with chronic hepatitis C who developed the characteristic triad of Ross syndrome within 1 month. The patient was otherwise healthy except for an aneurysm of the left medium brain artery not responsible for the syndrome.

[Congenital insensitivity to pain with anhidrosis associated with congenital myasthenic syndrome]

INTRODUCTION

Congenital insensitivity to pain with anhidrosis (CIPA) or hereditary sensory and autonomic neuropathy type IV (HSAN IV) is a rare autosomal recessive disorder featuring recurrent fever episodes, inability to sweat, absent response to noxious stimuli, self mutilating behavior and mental retardation. It has been associated with mutations in the NTRK1 gene, located in 1q21-22 and encoding a high-affinity NGF receptor.

CASE REPORT

An 8-year-old boy, the first son of consanguineous parents, presented with hypotonia, episodic hyperpyrexia and global developmental delay since the neonatal period. In addition to these signs, typical of CIPA, he displayed some other not previously described in this disease, such as facial dysmorphism, a severe swallowing disorder and a myogenic EMG pattern, that led to the initial suspicion of a muscle disorder. Molecular genetics studies uncovered a mutation c.C2011T in exon 15 of the NTRK1 gene. Genetic counselling was possible in the following pregnancy of the couple, where the female fetus was found to harbour the mutation in heterozygosity. The subsequent diagnosis of a congenital myasthenic syndrome in this sister led to neurophysiological re-evaluation of the probandus, in whom a myasthenic pattern of muscle activation was also found.

CONCLUSIONS

A patient with CIPA and congenital myasthenic syndrome is described. CIPA must be the first diagnostic hypothesis when assessing a patient with insensitivity to pain, anhidrosis and self-mutilation. Given the rather homogeneous presentation of CIPA, the occurrence of atypical myopathic manifestations should raise the suspicion of a concurrent disorder. The present consanguineous kindred illustrates a rare instance of transmission of two mutated alleles giving rise to two unrelated, infrequent neurological syndromes.

Generalised anhidrosis: different lesion sites demonstrated by microneurography and skin biopsy

Generalised anhidrosis (GA) shows a uniform clinical picture whether the pathogenesis involves intrinsic abnormalities of sweat glands or postganglionic sympathetic cholinergic nerve dysfunction. We describe two patients who presented intolerance to heat and anhidrosis. In the first patient, symptoms started at 33 years of age, and were associated with absent tendon reflexes and a mydriatic right pupil unreactive to light. The other patient had been unable to sweat since birth. GA was diagnosed on the basis of clinical findings and thermoregulatory tests. Microneurography and morphological analysis of the skin and its innervation disclosed a different lesion site underlying GA in the two patients, and distinguished between a postganglionic autonomic nerve fibre lesion and sweat gland dysfunction.

Idiopathic pure sudomotor failure: Anhidrosis due to deficits in cholinergic transmission

BACKGROUND

Acquired idiopathic generalized anhidrosis (AIGA) represents a heterogeneous clinical syndrome including sudomotor neuropathy and failure of the sweat glands. However, most AIGA cases comprise idiopathic pure sudomotor failure (IPSF), a distinct subgroup without sudomotor neuropathy or sweat gland failure.

METHODS

Eight patients with IPSF (mean +/- SD age 20 +/- 5 years) were assessed by thermoregulatory and pilocarpine-induced sweating tests, as well as emotional sweating using sudorometer (4 cases), microneurography of skin sympathetic nerve activity (2 cases), and skin biopsies from the forearm or axilla (3 cases).

RESULTS

Clinical features of IPSF comprise early onset; acute or sudden onset; concomitant sharp pain or cholinergic urticaria over the entire body; lack of autonomic dysfunction other than generalized anhidrosis; elevated serum IgE levels; and marked response to steroid. Sudomotor function testing revealed complete absence of thermoregulatory sweating, but well-preserved emotional sweating; pilocarpine did not induce sweating, and microneurography revealed that bursts of skin sympathetic nerve activity were not decreased; and skin biopsy displayed no morphologic abnormalities in sweat glands. The first two findings suggest lesions on the postsynaptic side of the nerve-sweat gland junction.

CONCLUSION

The lesions in IPSF may be in the muscarinic cholinergic receptors of sweat glands. Allergic mechanisms are probably involved in its pathophysiology.

The spectrum of autoimmune autonomic neuropathies

We analyzed the clinical characteristics of 18 patients (13 female, 5 male) who had autoimmune autonomic neuropathy (AAN) and ganglionic acetylcholine receptor (AChR) autoantibodies. Mean age was 61.4 years (standard deviation, 12.0 years). Ten patients had subacute symptom onset, six with an antecedent event. Eight patients had chronic AAN, characterized by insidious symptom onset, without antecedent event, and gradual progression. A majority of patients with high antibody values (>1.00 nmol/L) had a combination of sicca complex (marked dry eyes and dry mouth), abnormal pupillary light response, upper gastrointestinal symptoms, and neurogenic bladder. Chronic AAN segregated into two subgroups. One subgroup (N = 4) had low antibody titer (0.09 +/- 0.01 nmol/L) and a paucity of cholinergic symptoms. It was indistinguishable from pure autonomic failure. The other subgroup (N = 4) had high antibody titer (11.6 +/- 2.08 nmol/L), sicca complex, abnormal pupils, and neurogenic bladder; three had severe upper gastrointestinal dysfunction. Higher antibody titers correlated with greater autonomic dysfunction and more frequent cholinergic dysautonomia. These observations expand the clinical spectrum of AAN to include chronic cases, some being indistinguishable from pure autonomic failure, and support the concept that ganglionic AChR antibodies are important diagnostically and pathophysiologically in acquired dysautonomia.

Neurotransmitter specificity of sympathetic denervation in Parkinson's disease

In PD, orthostatic hypotension reflects sympathetic noradrenergic denervation. The authors assessed sympathetic cholinergic innervation by the quantitative sudomotor axon reflex test (QSART) in 12 patients who had sympathetic neurocirculatory failure, markedly decreased cardiac 6-[18F] fluorodopamine-derived radioactivity, and subnormal plasma norepinephrine increments during standing. All 12 had normal QSART results. The sympathetic nervous system lesion in PD involves loss of postganglionic catecholaminergic but not cholinergic nerves.

Is Ross syndrome a dysautonomic disorder only? An electrophysiologic and histologic study

OBJECTIVE

To define the involvement of peripheral nerve fibers in Ross syndrome.

METHODS

Mechanical pain perception, tactile and thermal thresholds on hand, foot dorsum, thigh, median nerve orthodromic sensory conduction velocity (SCV) and motor conduction velocity (MCV), sural nerve antidromic SCV, peroneal nerve MCV, H-reflex, F-wave, median, tibial nerve somatosensory evoked potentials (SSEPs), perioral, hand CO(2) laser late (LEPs) and ultralate evoked potentials, sympathetic skin response (SSRs), cardiovascular, Minor sweat, silastic imprint, histamine, photopletysmographic and pupil pilocarpine tests, cutaneous innervation immunohistochemical techniques were studied in 3 patients with Ross syndrome.

RESULTS

Quantitative sensory testing showed altered results in patients 1 and 2, and patient 3 had a slight impairment of mechanical pain perception. Nerve conduction, except for a median nerve distal reduction of sensory conduction in patient 1, F-wave and SSEP findings were normal; H-reflex was absent at rest in all patients. Hand LEPs were absent in patient 2, ultralate potentials were absent in patients 1 and 2. Skin biopsy showed a disease duration related reduction of unmyelinated and myelinated sensory fibers and a lack of unmyelinated autonomic fibers in all patients.

CONCLUSIONS

Our data suggest that Ross syndrome is a degenerative disorder involving progressive sudomotor fibers, and then epidermal sensory unmyelinated and myelinated fibers.

Physiologic assessment of autonomic dysfunction in pallidopontonigral degeneration with N279K mutation in the tau gene on chromosome 17

Autonomic function was investigated in five affected and five at-risk members of a single kinship of pallidopontonigral degeneration (PPND), which is a progressive syndrome of parkinsonism and frontotemporal dementia resulting from a mutation in the N279K tau gene on chromosome 17. Affected subjects reported symptoms including hyperhidrosis, sialorrhea, urinary frequency or incontinence, thermal intolerance, male sexual dysfunction, lacrimation, and dryness of the eyes or mouth. None had orthostatic hypotension. Autonomic testing revealed mild-to-moderate abnormalities in all five affected subjects and minor abnormalities in the three oldest, asymptomatic, at-risk subjects. Findings in affected subjects consisted of preganglionic sudomotor dysfunction in all five, impaired cardiovagal function in three, and reduced or absent pupillary near responses in four. Tests of adrenergic function were normal in all subjects. The degree of autonomic dysfunction correlated significantly with disease duration and with indices of disease severity. In conclusion, there is evidence in PPND of a disturbance in the central autonomic network.

Impaired sweating function in adult atopic dermatitis: results of the quantitative sudomotor axon reflex test

BACKGROUND

Impaired sweating is thought to be a cause of barrier dysfunction in atopic dermatitis (AD).

OBJECTIVES

To examine the sweating function in AD in a quantitative manner.

METHODS

We investigated the sweating response of lesional and non-lesional skin of adult patients with AD by a quantitative sudomotor axon reflex test in which the axon reflex is stimulated by acetylcholine iontophoresis. Sweat volume on the volar aspect of the forearm was measured in 18 adult patients with AD and in 40 non-atopic controls; five patients with Sjögren's syndrome were also studied as disease comparators. We also evaluated the sweating function in four AD patients after topical corticosteroid therapy. Latency time, direct (DIR) sweat volume and axon reflex-mediated indirect (AXR) sweat volume were the variables studied.

RESULTS

The latency time in AD patients was significantly prolonged and AXR sweat volume significantly reduced compared with those in non-atopic control subjects. The latency time and AXR sweat volume of lesional AD skin were significantly more prolonged and reduced, respectively, than those of non-lesional skin. In contrast, the DIR sweat volume of lesional or non-lesional AD skin induced by direct stimulation with acetylcholine was only slightly reduced when compared with that in non-atopic controls. Latency time and sweat volumes of lesional and non-lesional AD skin improved after topical corticosteroid therapy.

CONCLUSIONS

These results suggest that the impaired sweat response in AD is attributable to an abnormal sudomotor axon reflex, which is reversed by topical corticosteroid administration.

The circadian rhythm of body core temperature (CRT) is normal in patient with congenital generalized anhidrosis

The temperature of the human body is not constant during the day, and is related to a double modulation of both homeostatic and circadian processes. The circadian rhythm of body core temperature (CRT) is known to depend on the central mechanism involved in thermoregulatory variations. The role of sweating in the nocturnal fall of body core temperature (BcT) is not clear. We evaluated the CRT in a 45-year-old female with a lack of sweating since birth because of congenital generalized anhidrosis. She referred episodes of heat intolerance when ambient temperature was around 35 degrees C. Skin biopsies of both forearms and left axilla revealed atrophy and morphologic changes of eccrine glands. Neurological examination, nerve conduction studies, sympathetic skin response and cardiovascular reflex tests were normal. The study of CRT was performed by monitoring rectal temperature continuously in controlled conditions (ambient temperature 24 +/- 1 degrees C and humidity 40-50% in a light-dark schedule). The rhythmometric analysis showed normal 24-hour fluctuations. This case represents an "experiment of nature"demonstrating that the physiological nocturnal fall of BcT is independent of sweating.

Equine anhidrosis

The molecular basis of the pathophysiology of anhidrosis is still not well understood. Therefore, treatments are more often based on clinical impressions than on scientific fact. Treatment options for this condition will improve only when more is known about the molecular events that cause anhidrosis, especially as they relate to beta2-receptor dysfunction and stimulus-secretion coupling in the sweat glands of affected horses. Although this additional information is being attained, sound environmental management will continue to be a very important aspect of the treatment of horses affected with anhidrosis.

Incontinentia pigmenti in a surviving male is accompanied by hypohidrotic ectodermal dysplasia and recurrent infection

Familial Incontinentia pigmenti (IP) is a rare X-linked dominant condition. The affected cases have characteristic skin lesions, hair, eye, teeth and nail abnormalities and may also have neurological problems. The diagnosis has traditionally been made on clinical grounds. Segregation analysis has suggested that it is lethal in males. Only one liveborn male has been reported who died at one day of age. Female cases of IP survive because of the moderating effects of Lyonization. This child was the affected son of a female with IP. He had a novel phenotype consistent with hypohidrotic ectodermal dysplasia with immune deficiency (HED-ID) but with additional features: he had major problems with hematological disturbances, failure to thrive due to malabsorption, recurrent infections, generalized osteosclerosis and lymphedema of his lower limbs. He also demonstrated some typical features of IP with a generalized reticular skin hyperpigmentation, sparse hair and delayed eruption of teeth. The gene for NEMO (NF-kappa B Essential Modulator) has recently been shown to be mutated in cases of IP. Furthermore, most (80%) of patients possess a recurrent genomic rearrangement that deletes part of the gene resulting in an inactive NEMO protein. In the male case described here, a NEMO stop codon mutation has been identified that has arisen de novo in his affected mother. This mutation is likely to have a less severe effect on NEMO activity and may explain why this child survived for two years and 7 months.

Ross syndrome plus: beyond horner, Holmes-Adie, and harlequin

BACKGROUND

Ross syndrome is an uncommon disorder characterized by the triad of segmental anhidrosis, hyporeflexia, and tonic pupils.

METHODS

The authors describe the clinical findings of five patients with Ross syndrome and detail the results of their pharmacologic and autonomic testing.

RESULTS

In four patients, the classic findings of Ross syndrome were accompanied by Horner's syndrome. Other symptoms of dysautonomia were also common.

CONCLUSIONS

These findings suggest that Ross syndrome is a dysautonomic condition of varying expression resulting from a generalized injury to ganglion cells or their projections.

Anaesthetic management of children with congenital insensitivity to pain with anhidrosis

Congenital insensitivity to pain with anhidrosis (CIPA) is a rare sensory neuropathy, which affects patients' pain sensation and thermoregulation. There are several issues to consider when planning anaesthesia for those with this congenital disorder. Over a 20-year period, six patients with CIPA underwent 20 surgical procedures under general anaesthesia in our institution. We analysed our experience with these patients retrospectively. We conclude that patients with CIPA are able to undergo surgical procedures under general anaesthesia without major problems.

Predictive value of acetylcholine stimulation testing for oligohidrosis caused by zonisamide

We studied 16 patients for whom zonisamide was newly prescribed. Acetylcholine stimulation testing was performed about 1 month after zonisamide was initiated. Oligohidrosis occurred in none of the four with a normal response and in four of the 12 with a decreased response. Acetylcholine stimulation testing predicted oligohidrosis with a sensitivity of 1 and a false-positive rate of 0.67. The acetylcholine stimulation test was sensitive in detecting oligohidrosis caused by zonisamide, although the false-positive rate was high.

Congenital insensitivity to pain with anhidrosis (CIPA) in Israeli-Bedouins: genetic heterogeneity, novel mutations in the TRKA/NGF receptor gene, clinical findings, and results of nerve conduction studies

Congenital insensitivity to pain with anhidrosis (CIPA), a rare and severe disorder, comprises absence of sensation to noxious stimuli, inability to sweat, and recurrent episodes of hyperthermia. It has a relatively high prevalence in the consanguineous Israeli-Bedouins. Clinical studies of 28 patients are reported here. Using the linkage analysis approach, we linked the disease in 9 of 10 unrelated Israeli-Bedouin families with CIPA to the TrkA gene, which encodes the receptor for nerve growth factor. In one family, linkage was excluded, implying that another gene, yet unidentified, is involved. Two new mutations in the tyrosine kinase domain of the TrkA gene were identified in our CIPA patients: a 1926-ins-T in most of the southern Israeli-Negev CIPA patients, and a Pro- 689-Leu mutation in a different isolate of Bedouins in northern Israel. Eight prenatal diagnoses were made in the southern Israeli-Negev Bedouins, two by linkage analysis and six by checking directly for the 1926-ins-T mutation. Three polymorphisms in the TrkA protein kinase encoding domain were also observed.

Focal (segmental) dyshidrosis in syringomyelia

The features or mechanisms of dyshidrosis have not been sufficiently clarified. Neither has the difference between hyperhidrosis and hypohidrosis. To clarify the features and mechanisms of dyshidrosis (hyperhidrosis and hypohidrosis) in syringomyelia, the clinical features focusing on hidrosis of 30 patients with syringomyelia and Chiari malformation located from a syringomyelia database were prospectively analysed. The patients were classified into three groups: eight patients (26.7%) had segmental hypohidrosis, 10 (33. 3%) had segmental hyperhidrosis, and 12 (40.0%) had normohidrosis. We found that the Karnofsky functional status for the hyperhydrosis and normohidrosis groups were significantly higher than for the hypohidrosis group (p=0.0012), with no significant differences between the hyperhidrosis and normohidrosis groups. The duration from the onset of syringomyelia to the current dyshidrosis was significantly longer in the hypohidrosis group than in the hyperhidrosis group (p=0.0027). A significant correlation was identified between the duration from the onset of syringomyelia to the time at study and the performance score (r=-0.599, p=0.0003). The results substantiate previous hypotheses that in its early stage syringomyelia causes segmental hyperactivity of the sympathetic preganglionic neurons, and hyperactivity of these gradually subsides as tissue damage progresses. Focal hyperhidrosis may be regarded as a hallmark of a relatively intact spinal cord, as well as normohidrosis.

Cardiac sympathetic denervation in Ross syndrome demonstrated by MIBG-SPECT

We investigated cardiac sympathetic innervation by metaiodobenzylguanidine (MIBG) imaging in a patient with tonic pupils, loss of tendon reflexes, and segmental anhidrosis (Ross syndrome). Despite normal cardiovascular reflex tests, we observed a reduced global myocardial MIBG uptake as well as a regional uptake defect over the posterolateral cardiac territory indicating left ventricular peripheral sympathetic denervation. MIBG imaging seems to be a useful noninvasive diagnostic method for detection of early--possibly subclinical--cardiac autonomic impairment in Ross syndrome and provides further evidence of injury to postganglionic autonomic neurons as the underlying pathological mechanism of the disease.

The ultrastructural characteristics of eccrine sweat glands in a Fabry disease patient with hypohidrosis

As an investigation of the pathogenetic mechanism of diminished sweating in Fabry disease, an electron microscopy ultrastructural study was conducted on specimens of eccrine sweat glands from a typical patient with Fabry disease who had hypohidrosis, a low skin moisture content, and diminished thermoregulation ability. Numerous characteristic cytoplasmic inclusions were observed in the eccrine sweat glands, the lamellar pattern of which was considerably variable in various types of gland cells. Large vacuolar inclusions predominated in clear cells of secretory coil; lesser vacuoles were also seen in the coiled duct, and the basal cells of the straight duct toward the coiled duct displayed mulberry-like figures. There were some clear cells showing cell damage and necrosis in the secretory coil. Lamellated inclusions were noted in the unmyelinated axons innervating the eccrine sweat glands. The small blood vessels around the eccrine glands were narrowed by swollen endothelial cells with heavy inclusions. These intracytoplasmic deposits may be responsible for the decreased sweating ability in Fabry disease. The factors related to hypohidrosis are also discussed.

Nonneoplastic disorders of the eccrine glands

Eccrine glands are uniquely susceptible to a variety of pathologic processes. Alteration in the rate of sweat secretion manifests as hypohidrosis and hyperhidrosis. Obstruction of the eccrine duct leads to miliaria. The excretion of drugs into eccrine sweat may be a contributory factor in neutrophilic eccrine hidradenitis (NEH), syringosquamous metaplasia (SSM), coma bulla, and erythema multiforme (EM). Alterations in the electrolyte composition of eccrine sweat can be observed in several systemic diseases, most notably cystic fibrosis. This article summarizes current knowledge of eccrine gland pathophysiology.

Anhidrosis: an unusual presentation of diabetes insipidus

A 61-year-old man who had a 10-year history of anhidrosis was found to have idiopathic diabetes insipidus. He showed no spontaneous sweating or pilocarpine-induced sweat response. Skin pathology showed a normal eccrine gland. Microneurography detected no skin sympathetic nerve activity. Within a month of desmopressin treatment for diabetes insipidus, sweating and skin sympathetic nerve activity returned.

Heat stroke-like episode in a child caused by zonisamide

A 2-year-old mentally retarded boy with frontal lobe epilepsy presented with an episode that resembled heat stroke during the administration of zonisamide. He developed hyperpyrexia with oligohidrosis and central neurological symptoms, including, chorea-like involuntary movements, resting tremor, and cogwheel rigidity. A sweat test using pilocarpine iontophoresis revealed a marked reduction in the sweat response, which suggested a postganglionic sweating dysfunction. A skin biopsy examined by light and electron microscopy showed no morphological abnormality in the sweat glands. The oligohidrosis caused by zonisamide was reversible in that the patient regained the ability to sweat within 2 weeks of the cessation of drug administration. Children receiving zonisamide should be monitored for oligohidrosis and the development of neurological symptoms associated with an elevation of body temperature.

[Idiopathic segmental anhidrosis]

We described two cases of idiopathic segmental anhidrosis. Case 1 was a 47-year-old man, who noticed anhidrosis on the right side of face and chest during body heating. Case 2 was a 54-year-old woman, who complained of anhidrosis on the left side of face and upper chest during exercise. Both cases had neither somatic neurological deficit nor autonomic failure except for anhidrosis pupil size and deep tendon reflexes were normal. Reflex sweating to pilocarpine was exaggerated in the anhidrotic areas in both cases, suggesting lesions in the preganglionic sudomotor nerves. Abnormal laboratory finding was elevated serum rheumatoid factor level in only case 2. Segmental anhidrosis was static for 1.5 year and one year, respectively. The previous literature contains similar four cases. Idiopathic segmental anhidrosis may be an abortive form of Ross' syndrome (tonic pupil, hyporeflexia and segmental anhidrosis).

Possible mechanism of anhidrosis in a symptomatic female carrier of Fabry's disease: an assessment by skin sympathetic nerve activity and sympathetic skin response

Fabry's disease, X-linked alpha-galactosidase deficiency, features a variety of autonomic abnormalities including anhidrosis. In this study, we measured the skin sympathetic nerve activity (SSNA), skin potential and sweat rate in a symptomatic female carrier to investigate the underlying pathophysiology of anhidrosis. The basal activity and responsiveness of SSNA were both fairly well preserved, although slightly reduced compared with the control levels. However, sweating was completely absent, despite the normal skin potential change in response to SSNA bursts. These results suggest that anhidrosis in Fabry's disease is a result of sweat gland dysfunction as well as abnormal SSNA.