Position Statement: Linear prurigo is a subtype of chronic prurigo

BACKGROUND

Chronic prurigo (CPG) is a distinct disease characterized by chronic pruritus, history and/or signs of prolonged scratching and multiple pruriginous lesions. It may present with various clinical manifestations, including papules, nodules, plaques or umbilicated lesions. Some patients with chronic pruritus show pruriginous linear and scaring scratch lesions (LSSL) and it is unclear whether these lesions belong to the spectrum of CPG.

OBJECTIVE

To achieve a consensus on the classification of pruriginous LSSL and establish criteria to differentiate them from similar appearing conditions of different nature.

METHODS

Members of the Task Force Pruritus (TFP) of the European Academy of Dermatology and Venereology participated in the consensus conference, discussing representative clinical cases. Using the Delphi method, consensus was reached when ≥75% of members agreed on a statement.

RESULTS

Twenty-one members of the TFP with voting rights participated in the meeting. It was consented that LSSL occurs due to chronic pruritus and prolonged scratching, and share common pathophysiological mechanisms with CPG. LSSL were thus considered as belonging to the spectrum of CPG and the term 'linear prurigo' was chosen to describe this manifestation.

CONCLUSION

Considering linear prurigo as belonging to the spectrum of CPG has important clinical implications, since both the diagnostic and therapeutic approach of these patients should be performed as recommended for CPG. Importantly, linear prurigo should be differentiated from self-inflicted skin lesions as factitious disorders or skin picking syndromes. In the latter, artificial manipulation rather than pruritus itself leads to the development of cutaneous lesions, which can show clinical similarities to linear prurigo.

The genetic basis for most patients with pustular skin disease remains elusive

BACKGROUND

Rare variants in the genes IL36RN, CARD14 and AP1S3 have been identified to cause or contribute to pustular skin diseases, primarily generalized pustular psoriasis (GPP).

OBJECTIVES

To better understand the disease relevance of these genes, we screened our cohorts of patients with pustular skin diseases [primarily GPP and palmoplantar pustular psoriasis (PPP)] for coding changes in these three genes. Carriers of single heterozygous IL36RN mutations were screened for a second mutation in IL36RN.

METHODS

Coding exons of IL36RN, CARD14 and AP1S3 were sequenced in 67 patients - 61 with GPP, two with acute generalized exanthematous pustulosis and four with acrodermatitis continua of Hallopeau. We screened IL36RN and AP1S3 for intragenic copy-number variants and 258 patients with PPP for coding changes in AP1S3. Eleven heterozygous IL36RN mutations carriers were analysed for a second noncoding IL36RN mutation. Genotype-phenotype correlations in carriers/noncarriers of IL36RN mutations were assessed within the GPP cohort.

RESULTS

The majority of patients (GPP, 64%) did not carry rare variants in any of the three genes. Biallelic and monoallelic IL36RN mutations were identified in 15 and five patients with GPP, respectively. Noncoding rare IL36RN variants were not identified in heterozygous carriers. The only significant genotype-phenotype correlation observed for IL36RN mutation carriers was early age at disease onset. Additional rare CARD14 or AP1S3 variants were identified in 15% of IL36RN mutation carriers.

CONCLUSIONS

The identification of IL36RN mutation carriers harbouring additional rare variants in CARD14 or AP1S3 indicates a more complex mode of inheritance of pustular psoriasis. Our results suggest that, in heterozygous IL36RN mutation carriers, there are additional disease-causing genetic factors outside IL36RN.

[Topical interferon-beta: an additional treatment for ulcerated mycosis fungoides]

The combination of systemic interferon-alpha and systemic photochemotherapy is one of the most effective and most frequently administered treatment regimens for mycosis fungoides. Two patients with mycosis fungoides stage IIb with ulcerated tumors were treated with this regimen. While the plaques responded favorably to the combination therapy, the ulcerated tumors were quite resistant despite treatment for several weeks. When topical interferon-beta in a gel base was added to the regimen, a rapid resolution of the tumors was noticed. This observation suggests topical interferon-beta may be an effective adjuvant strategy to be combined with systemic therapy.

Topical pimecrolimus and tacrolimus transiently induce neuropeptide release and mast cell degranulation in murine skin

BACKGROUND

The topical calcineurin inhibitors pimecrolimus and tacrolimus have been demonstrated to be an effective new anti-inflammatory therapy. The only clinically relevant side-effect reported is transient application site burning and stinging itch at the beginning of topical therapy.

OBJECTIVES

In order to understand the underlying mechanism of this effect, we examined whether or not the compounds are able to stimulate neuropeptide release in normal murine skin as well as in a mouse model of experimentally induced irritant contact dermatitis.

METHODS

Balb/c mice were treated with 1% pimecrolimus cream or 0.1% tacrolimus ointment. Untreated and corresponding vehicle-treated mice served as controls. Skin specimens were investigated by light, immunofluorescence and electron microscopy as well as enzyme-linked immunosorbent assay and polymerase chain reaction.

RESULTS

Topical application of pimecrolimus and tacrolimus was followed by an initial release of substance P and calcitonin gene-related peptide from primary afferent nerve fibres in murine skin during the early inflammatory response. The release of the neuropeptides and their binding to mast cells (MCs) led to MC degranulation. Mediators of MCs such as histamine and tryptase may induce pruritus and burning by binding to the corresponding receptors (histamine receptor 1, proteinase-activated receptor 2) on sensory nerve fibres, which explains the initial side-effects during therapy with calcineurin inhibitors.

CONCLUSIONS

It may be speculated that calcineurin inhibitors directly stimulate intracellular signalling pathways or bind to ion channels such as transient receptor potential vanilloid 1 or receptors involved in nociception.

Topical pimecrolimus and tacrolimus transiently induce neuropeptide release and mast cell degranulation in murine skin

BACKGROUND

The topical calcineurin inhibitors pimecrolimus and tacrolimus have been demonstrated to be an effective new anti-inflammatory therapy. The only clinically relevant side-effect reported is transient application site burning and stinging itch at the beginning of topical therapy.

OBJECTIVES

In order to understand the underlying mechanism of this effect, we examined whether or not the compounds are able to stimulate neuropeptide release in normal murine skin as well as in a mouse model of experimentally induced irritant contact dermatitis.

METHODS

Balb/c mice were treated with 1% pimecrolimus cream or 0.1% tacrolimus ointment. Untreated and corresponding vehicle-treated mice served as controls. Skin specimens were investigated by light, immunofluorescence and electron microscopy as well as enzyme-linked immunosorbent assay and polymerase chain reaction.

RESULTS

Topical application of pimecrolimus and tacrolimus was followed by an initial release of substance P and calcitonin gene-related peptide from primary afferent nerve fibres in murine skin during the early inflammatory response. The release of the neuropeptides and their binding to mast cells (MCs) led to MC degranulation. Mediators of MCs such as histamine and tryptase may induce pruritus and burning by binding to the corresponding receptors (histamine receptor 1, proteinase-activated receptor 2) on sensory nerve fibres, which explains the initial side-effects during therapy with calcineurin inhibitors.

CONCLUSIONS

It may be speculated that calcineurin inhibitors directly stimulate intracellular signalling pathways or bind to ion channels such as transient receptor potential vanilloid 1 or receptors involved in nociception.

[Anaphylactoid reaction in occult systemic mastocytosis. A rare dermatologic emergency ]

With the occurrence of unclear consciousness conditions primarily internal or neurological causes are considered. Of a systemic mastocytosis one thinks only rarely, which can accompany without or with slight clinically visible skin changes. In the following we report on a patient who has repeated unclear shock conditions and required resuscitation several times without a recognizable cause, with whom a systemic mastocytosis could be proven. Clinically very discrete lesions of mastocytosis were recognizable from the skin. Only an increased tryptase level referred to being present an occult systemic mastocytosis. The diagnostics, potential triggers and therapy of this disease are to be discussed on the basis the available case.

[Squamous epithelial carcinomas of the face with neurotropic growth]

BACKGROUND AND OBJECTIVE

Invasion of squamous cell carcinoma of the head and neck into cutaneous nerves is rare and can easily be missed. Perineural outgrowth into cerebral nerves may result in severe pain or neurological disturbances. In addition, these carcinomas more often recur or metastasize and therefore are associated with a poor prognosis.

PATIENTS/METHODS

We report on two patients with squamous cell carcinoma of the dorsum of the nose and lower lip exhibiting neurotropic growth.

RESULTS

Histology showed pleomorphic keratinocytes growing deep into the subcutaneous tissue and bone, respectively. The presence of few pleomorphic keratinocytes could be only confirmed by immunohistochemistry, though indicated by a perineural lymphocytic infiltrate. In both patients, several re-excisions were necessary to achieve cure.

CONCLUSIONS

In neurotropic squamous cell carcinoma a consequent radical micrographic surgery as well as neurological and radiological investigations are mandatory. We also review the literature.

[Wax model collection of the Department of Dermatology, University of Münster]

Between the 17th century and the middle of the 20th century, wax models were widely used for training in anatomy and other medical fields, especially dermatology. Thereafter, photographic techniques led to the replacement and subsequent dissolution of many European wax model collections. Unfortunately many wax models lose their original colors over time. Since only few mouleurs (wax artists) are still active in Europe conserving wax models, the "dying of moulages" cannot be stopped. Consequently, the existing wax models are of medical and historical interest since they reflect the development of our speciality. The Department of Dermatology in Münster is in the possession of 121 wax models, which are presented in this article.

Differential storage of hydroxyethyl starch (HES) in the skin: an immunoelectron-microscopical long-term study

Hydroxyethyl starch (HES) is widely used as a plasma substitute. Serious side effects occur only rarely, whereas a high incidence of severe pruritus has been reported. Moreover, tissue storage of HES has been demonstrated in various organs. The aim of the current study has been to examine precisely the intracellular uptake and long-term storage of HES in the skin. Skin biopsies from 119 patients who received HES of various preparations and cumulative dosage were obtained 30 min to 130 months after infusion therapy. The samples were analysed by ultrastructural and immunoelectron microscopy with HES-specific monoclonal and polyclonal antibodies. A characteristic vacuolisation of perivascular histiocytes was a regular finding in all skin biopsies as early as 1 day after a single infusion of 30 g. Immunoreactivity for HES was demonstrable within the vacuoles. Generally, the size and number of vacuoles in the histiocytes increased concomitantly with the cumulative dosage. Following administration of higher HES dosages, vacuoles were demonstrable in endothelial cells of blood and lymphatic vessels, basal keratinocytes, epithelia of sweat glands and in small peripheral nerves, the last mentioned being associated with pruritus. A subsequent reduction of the vacuoles in size and number could be demonstrated within 52 months. In nerves, HES deposits persisted no longer than 17 months paralleling the cessation of pruritus. Biopsies taken after 94 months exhibited no HES deposits in the skin. The condensation and final dissolution of the vacuoles may either indicate the release and subsequent redistribution of HES into the circulation or lysosomal degradation.

[Incidence of fungal involvement in nail psoriasis]

BACKGROUND AND OBJECTIVE

Because it is clinically so similar, onychomycosis is one of the most important differential diagnostic considerations in psoriatic nail changes. We determined the frequency of fungal involvement in nails of psoriatic patients.

PATIENTS/METHODS

Fungal colonization of the nails of psoriatic patients with and without clinically obvious nail changes was investigated in a collective of 250 patients compared to a group of 102 non-psoriatic persons.

RESULTS

There was no significant difference in the frequency of nail colonization with dermatophytes and moulds between healthy persons and psoriatics. Yeasts were more commonly found in psoriatic nails.

CONCLUSIONS

Nail changes in psoriatic patients are mostly caused by psoriasis. However secondary colonization by yeasts is more common in psoriatic nails than in the general population. It remains to be clarified why dermatophytes are not more common in psoriatic nails.

UVA rush hardening for the treatment of solar urticaria

Induction of tolerance by subsequent UV exposures is the most effective therapy for solar urticaria; however, it is time-consuming and takes a long time until protection is achieved. Three patients with solar urticaria were exposed to multiple UVA irradiations at 1-hour intervals per day. With this rush hardening regimen, protection was achieved within 3 days.