Chloracne and chloracnegens

Potential impact of the 2023 Lahaina wildfire on the marine environment: Modeling the transport of ash-laden benzo[a]pyrene and pentachlorophenol

The Lahaina urban/wildland fire event is considered the deadliest wildfire in the past century of U.S. history. This fire resulted in over 2200 building structures destroyed or damaged, approximately 4000 automobiles were incinerated and between 450 and 878 ha of grassland burned in areas adjoining the town of Lahaina, Maui County, State of Hawaii, U.S.A. One of the most abundant contaminants of both wildland and urban fires is the incomplete combustion product, benzo[a]pyrene. Pentachlorophenol from burned and unburned utility poles/residential burn sites enter into navigable waters, thus posing a serious risk to the water quality of coastal waters. The Risk Quotient Plumes for benzo[a]pyrene and pentachlorophenol, mobilized from Lahaina into coastal waters were calculated based on a hydrodynamic analysis and an integrated ecological risk assessment. This plume was simulated using rainfall events in November 2022 as a proxy for the first major rainfall event expected in Lahaina in 2024. The models indicated that the estimated levels of benzo[a]pyrene and pentachlorophenol posed a risk to near shore habitants within 2 km of Lahaina. The levels of pentachlorophenol were more widespread than benzo[a]pyrene and were predicted to pose a hazard to marine life as far away as Molokini Shoal Marine Life Conservation District and 'Āhihi-Kīna'u Natural Area Reserve. Fisheries species captured near these areas should be tested for consumption safety.

Therapeutic Agents with AHR Inhibiting and NRF2 Activating Activity for Managing Chloracne

Chloracne is the major skin symptom caused by dioxin intoxication. Dioxin activates the aryl hydrocarbon receptor (AHR)–cytochrome p450 1A1 (CYP1A1) system, generates oxidative stress, and induces hyperkeratinization of keratinocytes and sebocytes leading to chloracne. Nuclear factor-erythroid 2-related factor-2 (NRF2) is a master switch that induces the expression of various antioxidative enzymes, such as heme oxygenase-1. Cinnamaldehyde is an antioxidant phytochemical that inhibits AHR–CYP1A1 signaling and activates the NRF2–antioxidative axis. The cinnamaldehyde-containing Kampo herbal medicine Keishibukuryogan is capable of improving chloracne in Yusho patients who are highly contaminated with dioxin. Agents with dual functions in promoting AHR–CYP1A1 inhibition and NRF2 activation may be useful for managing dioxin-related health hazards.

Perianal Comedones: A Rare Incidental Finding

Comedones occur when an overproliferation of keratinocytes blocks sebum secretion in a pilosebaceous duct. Comedones have multiple possible etiologies and contributing factors. While comedones are common to acne, they are also seen in occupational exposures and are associated with certain syndromes. We describe a particularly rare case of comedones at the perianus that is not associated with any known exposure or disease and is a rare incidental finding.

SRB1 as a new redox target of cigarette smoke in human sebocytes

For its critical location, the skin represents the major interface between the body and the environment, therefore is one of the major biological barriers against the outdoor environmental stressors. Among the several oxidative environmental stressors, cigarette smoke (CS) has been associated with the development and worsening of many skin pathologies such as acne, dermatitis, delayed wound healing, aging and skin cancer. In our previous work we have demonstrated that CS is able to affect genes involved in skin cholesterol trafficking, among which SRB1, a receptor involved in the uptake of cholesterol from HDL, seems to be very susceptible to the oxidative stress induced by CS. In the present work we wanted to investigate the presence of SRB1 in human sebocytes and whether CS can affect cholesterol cellular uptake via the redox modulation of SRB1. By using a co-culture system of keratinocytes/sebocytes, we found that CS exposure induced a SRB1 protein loss without affecting sebocytes viability. The decrease of SRB1 levels was a consequence of SRB1/HNE adducts formation that leads to SRB1 ubiquitination and degradation. Moreover, the CS-induced loss of SRB1 induced an alteration of sebocytes lipid content, also demonstrated by cholesterol quantification in SRB1 siRNA experiments. In conclusion, exposure to CS, induced SRB1 post-translational modifications in sebocytes and this might affect sebocytes/skin functionality.

Current skin symptoms of Yusho patients exposed to high levels of 2,3,4,7,8-pentachlorinated dibenzofuran and polychlorinated biphenyls in 1968

Yusho was a mass food poisoning event due to the ingestion of rice oil contaminated with polychlorinated biphenyls (PCBs) and various dioxins and dioxin-like compounds. At its outbreak in 1968, Yusho patients suffered severe skin symptoms. Although the blood concentrations of PCBs and dioxins, especially highly toxic 2,3,4,7,8-pentachlorinated dibenzofuran (2,3,4,7,8-PeCDF) remain high in these patients, extensive analysis has not been performed on their current skin symptoms. We categorized and evaluated the specific skin symptoms in Yusho in 2012 by grading their severity using an arbitrary scoring system, and analyzed their correlations with the blood concentrations of 2,3,4,7,8-PeCDF and PCBs. A total of 352 Yusho patients underwent annual dermatological check-ups, in which five skin symptoms: black comedones, acneiform eruptions, scar formation, pigmentation and nail deformity, were evaluated for their distribution and severity. Approximately one-third of Yusho patients still presented with black comedones, acneiform eruptions and scar formation; the distributions of these symptoms were similar to those at the time of the Yusho outbreak. The mean blood concentrations of 2,3,4,7,8-PeCDF and total PCBs in Yusho patients were still higher than those in controls. The prevalence and severity of black comedones were correlated with age. Severity scores of black comedones and scar formation were positively correlated with 2,3,4,7,8-PeCDF blood level, and those of black comedones, scar formation, and pigmentation were positively correlated with total PCBs blood level. This study suggests that 2,3,4,7,8-PeCDF and PCBs remaining in Yusho patients still play crucial roles in the development of skin symptoms in Yusho.

Occluded Cigarette Smoke Exposure Causing Localized Chloracne-Like Comedones

Many environmental acne disorders, including chloracne and oil acne, were previously thought to occur predominantly in occupational settings following polycyclic aromatic hydrocarbon exposure. Cigarette smoke has also been shown to contain a large number of these toxic polycyclic aromatic hydrocarbon components and strictly correlates with noninflammatory acneiform lesion development in postadolescent patients. We report a case of localized open comedones associated with occluded cigarette smoke exposure near the nasal cavity due to infrequently changed gauze following rhinectomy. The dermal uptake of polycyclic aromatic hydrocarbon components in cigarette smoke has the potential to function as a contributing factor in chloracne development. Several of these environmental and noninflammatory acne subtypes may share a common molecular propensity for enhanced comedogenesis originating from aryl hydrocarbon receptor pathway effects in the skin. Additional studies are needed to further elucidate the exact mechanistic pathways through which tobacco smoke impacts the integumentary system.

Skin diseases associated with Agent Orange and other organochlorine exposures

Organochlorine exposure is an important cause of cutaneous and systemic toxicity. Exposure has been associated with industrial accidents, intentional poisoning, and the use of defoliants, such as Agent Orange in the Vietnam War. Although long-term health effects are systematically reviewed by the Institute of Medicine, skin diseases are not comprehensively assessed. This represents an important practice gap as patients can present with cutaneous findings. This article provides a systematic review of the cutaneous manifestations of known mass organochlorine exposures in military and industrial settings with the goal of providing clinically useful recommendations for dermatologists seeing patients inquiring about organochlorine effects. Patients with a new diagnosis of chloracne, porphyria cutanea tarda, cutaneous lymphomas (non-Hodgkin lymphoma), and soft-tissue sarcomas including dermatofibrosarcoma protuberans and leiomyosarcomas should be screened for a history of Vietnam service or industrial exposure. Inconclusive evidence exists for an increased risk of other skin diseases in Vietnam veterans exposed to Agent Orange including benign fatty tumors, melanomas, nonmelanoma skin cancers, milia, eczema, dyschromias, disturbance of skin sensation, and rashes not otherwise specified. Affected veterans should be informed of the uncertain data in those cases. Referral to Department of Veterans Affairs for disability assessment is indicated for conditions with established associations.

AhR signalling and dioxin toxicity

Dioxins are a family of molecules associated to several industrial accidents such as Ludwigshafen in 1953 or Seveso in 1976, to the Agent Orange used during the war of Vietnam, and more recently to the poisoning of the former president of Ukraine, Victor Yushchenko. These persistent organic pollutants are by-products of industrial activity and bind to an intracellular receptor, AhR, with a high potency. In humans, exposure to dioxins, in particular 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces a cutaneous syndrome known as chloracne, consisting in the development of many small skin lesions (hamartoma), lasting for 2-5 years. Although TCDD has been classified by the WHO as a human carcinogen, its carcinogenic potential to humans is not clearly demonstrated. It was first believed that AhR activation accounted for most, if not all, biological properties of dioxins. However, certain AhR agonists found in vegetables do not induce chloracne, and other chemicals, in particular certain therapeutic agents, may induce a chloracne-like syndrome without activating AhR. It is time to rethink the mechanism of dioxin toxicity and analyse in more details the biological events following exposure to these compounds and other AhR agonists, some of which have a very different chemical structure than TCDD. In particular various food-containing AhR agonists are non-toxic and may on the contrary have beneficial properties to human health.

Drug-induced acneiform eruption

Drug-induced acne is a specific subset of acne that usually has some specific features, namely a monomorphic pattern, an unusual location of the lesions beyond the seborrheic areas, an unusual age of onset, a resistance to conventional acne therapy and, of course, the notion of a recent drug introduction. Many drugs can be responsible for such a clinical pattern. Corticosteroids, neuropsychotherapeutic drugs, antituberculosis drugs, and immunomodulating molecules are the more classical drugs associated with induced acne. Recently, new drugs, mainly targeted therapy in the field of oncology, such as epidermal growth factor receptor inhibitors, have been associated with an increased frequency of this adverse effect. Disruption of the culprit drug is rarely mandatory in cases of drug-induced acne. Close cooperation between the dermatologist and medical staff in charge of the patient is an important challenge to achieve optimal management of the initial disease.

Environmental pollution and acne: Chloracne

Environmental pollutants can result in a variant of acne called 'chloracne'. Chloracne is caused by systemic exposure to certain halogenated aromatic hydrocarbons 'chloracnegens', and is considered to be one of the most sensitive indicators of systemic poisoning by these compounds. Dioxin is the most potent environmental chloracnegen. Most cases of chloracne have resulted from occupational and non-occupational exposures, non-occupational chloracne mainly resulted from contaminated industrial wastes and contaminated food products. Non-inflammatory comedones and straw-colored cysts are the primary clinical manifestation of chloracne. Increasing of cysts in number is a signal of aggravation of chloracne. Generalized lesions can appear on the face, neck, trunk, exterimities, genitalia, axillary and other areas. Course of chloracne is chronic. Severity of chloracne is related to dosage of exposed chloracnegens, chloracnegenic potency and individual susceptibility. Histopathology of chloracne is characterized mainly by hyperplasia of epidermal cell, while follicular and sebaceous gland are taken placed by keratinized epidermal cell. The pathogenesis of chloracne maybe related to the imbalance of epidermal stem cell. Chloracne appears to be resistant to all tested forms of treatment. The only way to control chloracne is to prevent exposure to chloracnegens.

Inflammatory and chloracne-like skin lesions in B6C3F1 mice exposed to 3,3',4,4'-tetrachloroazobenzene for 2 years

Exposure to dioxin and dioxin-like compounds (DLCs) has been connected to the induction of chloracne in humans and animals. 3,3',4,4'-Tetrachloroazobenzene (TCAB) is an environmental contaminant that induces chloracne in humans. TCAB has been studied only to a limited extent in laboratory animals. While performing a 2-year gavage study in B6C3F1 mice to evaluate the toxic and carcinogenic effects of TCAB, we also explored potential chloracnegenic properties. Groups of 50 male and 50 female B6C3F1 mice were exposed by gavage to TCAB at dose levels of 0, 3, 10 and 30 mg/kg for 5 days a week for 2 years. The animals developed treatment-related gross inflammatory skin lesions, which were characterized histologically by inflammation, fibrosis, hyperplasia, and ulcers. Additionally, many of the animals developed follicular dilatation and sebaceous gland atrophy, consistent with chloracne-like lesions. This current 2-year study supports recently published papers showing susceptibility to chloracne in mouse strains other than hairless mice. The chloracne-like lesions were not clinically evident; therefore, our study highlights the need for careful examination of the skin in order to identify subtle lesions consistent with chloracne-like changes in rodents exposed to dioxin and DLCs. Since previous short-term studies did not demonstrate any skin lesions, we suggest that reliable assessment of all safety issues involving dioxin and DLCs requires evaluation following chronic exposure. Such studies in animal models will help to elucidate the mechanisms of dioxin-related health hazards.

Chloracne in seven organic chemists exposed to novel polycyclic halogenated chemical compounds (triazoloquinoxalines)

Chloracne is an acneiform eruption caused though poisoning by aromatic compounds (usually halogenated) showing a specific molecular configuration. We describe an outbreak of chloracne among seven discovery chemists who synthesized novel polycyclic halogenated chemical compounds which were classified as triazoloquinoxalines, not known to be chloracnegenic. The diagnosis of chloracne, made clinically, elicited a thorough risk assessment and monitoring programme by the occupational health department. The chemists were investigated by serum excretion rates, skin sampling for Propionibacterium acnes, skin biopsy and laboratory blood investigations. Sebum excretion was normal in five cases, raised in one case and severely reduced in another. Skin levels of P. acnes were normal in all patients except for the one subject who had low sebum excretion, in whom they were undetectable. One subject had a slightly raised serum level of alanine aminotransferase. There were no other signs of systemic toxicity. Two subjects were treated with an oral antibiotic, two received topical therapy only and three required no treatment at all. The patients have had thorough health surveillance at 6-monthly and yearly intervals. In each case the chloracne mostly resolved within 18-24 months although on examination about 3 years later, five of the seven still showed minor changes of chloracne. This outbreak emphasizes the need for vigilance in discovery science. The triazoloquinoxalines were not previously recognized as being chloracnegens although their chemical characteristics were subsequently identified as being in keeping with other chemicals that can cause chloracne. Chloracne can be a difficult diagnosis to make when it occurs in a novel setting: occupational physicians and dermatologists need to be vigilant when dealing with unusual eruptions in discovery chemists.

Acquired palmoplantar keratoderma

Palmoplantar keratodermas (PPKs) are a diverse entity of disorders that are characterized by abnormal thickening of the skin on the palms and soles. Traditionally they have been classified as either hereditary or acquired and are distinguished from each other on the basis of mode of inheritance, presence of transgrediens (defined as contiguous extension of hyperkeratosis beyond the palmar and/or plantar skin), co-morbidities with other symptoms, and extent of epidermal involvement, namely diffuse, focal, and punctate. As the terms hyperkeratosis and keratoderma have been used interchangeably throughout the literature, we define acquired keratoderma as a non-hereditary, non-frictional hyperkeratosis of the palms and/or soles that involves >/=50% of the surface of involved acral areas and that may or may not be associated with clinical and histologic inflammation. Given the numerous possible underlying causes for acquired PPKs, evaluation of patients presenting with acquired PPK can be a perplexing task. To facilitate such evaluations, this review categorizes the acquired PPKs as: keratoderma climactericum, drug related, malnutrition associated, chemically induced, systemic disease related, malignancy associated, dermatoses related, infectious, and idiopathic. In order to avoid the possibility of overlooking an underlying etiology and to eliminate excessive testing, we present an algorithm for assessing patients presenting with acquired PPK. The first step should include a comprehensive history and a physical examination, including a complete skin examination. If findings are consistent with a hereditary keratoderma, then a genetics consultation should be considered. Any findings suggestive of underlying conditions should be aggressively evaluated and treated. If no pertinent findings are identified after a history and a physical examination, laboratory and radiology studies should be undertaken in a systematic, logical fashion. In terms of treatment, the most successful results occur when the underlying etiology is diagnosed and treated. If no such etiology is evident, then conservative treatment options include topical keratolytics (urea, salicylic acid, lactic acid), repeated physical debridement, topical retinoids, topical psoralen plus UVA, and topical corticosteroids. Etretinate and acitretin have also shown some success as alternative treatments in recalcitrant cases.

Dioxin-induced chloracne--reconstructing the cellular and molecular mechanisms of a classic environmental disease

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is among the most toxic pollutants known to date that serves as a prototype for a group of halogenated hydrocarbon compounds characterized by extraordinary environmental persistence and unique ability to concentrate in animal and human tissues. TCDD can elicit a complex array of pleiotropic adverse effects in humans, although chloracne, a specific type of acne-like skin disease, is the only consistent manifestation of dioxin intoxication, thus representing a 'hallmark' of TCDD exposure. Chloracne is considered to be one of the most specific and sensitive biomarkers of TCDD intoxication that allows clinical and epidemiological evaluation of exposure level at threshold doses. The specific cellular and molecular mechanisms involved in pathogenesis of chloracne are still unknown. In this review, we summarize the available clinical data on chloracne and recent progress in understanding the role of the dioxin-dependent pathway in the control of gene transcription and discuss molecular and cellular events potentially involved in chloracne pathogenesis. We propose that the dioxin-induced activation of skin stem cells and a shift in differentiation commitment of their progeny may represent a major mechanism of chloracne development.

Health status and plasma dioxin levels in chloracne cases 20 years after the Seveso, Italy accident

BACKGROUND

The Seveso, Italy accident of 1976 exposed a large population to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD or simply dioxin). The accident resulted, mostly among children, in one of the largest ever-reported outbreaks of chloracne, the typical skin disorder due to halogenated-hydrocarbon compounds.

OBJECTIVES

Approximately 20 years after the accident, we conducted an epidemiological study in Seveso to investigate (a) the health status of chloracne cases; (b) TCDD-chloracne exposure-response relationship; and (c) factors modifying TCDD toxicity.

METHODS

From 1993 to 1998, we recruited 101 chloracne cases and 211 controls. Trained interviewers administered a structured questionnaire assessing, among other epidemiological variables, information on an extensive list of diseases. During the interview, individual pigmentary characteristics were determined. We measured plasma TCDD levels using high-resolution gas chromatography/mass spectrometry.

RESULTS

Plasma TCDD was still elevated (> 10 ppt) in 78 (26.6%) of the 293 subjects with adequate plasma samples, particularly in females, in subjects who had eaten home-grown animals, and in individuals with older age, higher body mass index and residence near the accident site. After 20 years, health conditions of chloracne cases were similar to those of controls from the Seveso area. Elevated plasma TCDD was associated with chloracne [odds ratio (OR) = 3.7, 95% confidence interval (CI) 1.6-8.8, adjusted for age, sex and residence]. Chloracne risk was higher in subjects younger than 8 years at the accident (OR = 7.4, 95% CI 1.8-30.3) and, contrary to previous hypotheses, did not increase at puberty onset or in teenage years. Subjects with elevated TCDD levels and light hair colour had higher relative odds of chloracne (OR = 9.2, 95% CI 2.6-32.5).

CONCLUSIONS

Dioxin toxicity in chloracne cases was confined to the acute dermatotoxic effects. Chloracne occurrence appeared related to younger age and light hair colour. Age-related dioxin elimination or dilution must be taken into account in interpreting these results.

Acquired disorders of elastic tissue: part I. Increased elastic tissue and solar elastotic syndromes

Elastic fibers in the extracellular matrix are an integral component of dermal connective tissue. The resilience and elasticity required for normal structure and function of the skin may be attributed to the network of elastic tissue. Advances in our understanding of elastic tissue physiology provide a foundation for studying the pathogenesis of elastic tissue disorders. Many acquired disorders are nevertheless poorly understood due to the paucity of reported cases. Several acquired disorders in which accumulation or elastotic degeneration of dermal elastic fibers produces prominent clinical and histopathologic features have recently been described. They include elastoderma, linear focal elastosis, and late-onset focal dermal elastosis and must be differentiated from better-known disorders, among them acquired pseudoxanthoma elasticum, elastosis perforans serpiginosa, and Favré-Racouchot syndrome. Learning objective At the conclusion of this learning activity, participants should understand the similarities and differences between acquired disorders of elastic tissue that are characterized by an increase in elastic tissue, as well as the spectrum of solar elastotic dermatoses.

MAPK signaling pathways modulate IL-1β expression in human keratinocytes

The signaling pathways that modulate IL-1beta expression in human keratinocytes have not been well defined. We have previously shown that TCDD-stimulated AhR-dependent IL-1beta expression in human keratinocytes is due to posttranscriptional regulation involving mRNA stabilization. Since TCDD activates a variety of cellular signaling pathways such as PKC, JNK, and ERK, we investigated these pathways to determine their roles in TCDD-stimulated IL-1beta expression in the human keratinocyte cell line SCC-12F. In this study, we used specific signaling inhibitors to show that ERK and JNK, but not transglutaminase, PKC, or p38, signaling modulate IL-1beta expression. In addition, we show that ERK is constitutively active and unaffected by TCDD treatment and differentiation, while the JNK signaling pathway is modulated by TCDD in an AhR-dependent manner. Thus, both the ERK and JNK MAPK pathways are necessary for IL-1beta expression in TCDD-stimulated human keratinocytes, however, they act at different levels to modulate IL-1beta expression.

Aryl hydrocarbon receptor-mediated posttranscriptional regulation of IL-1beta

TCDD stimulated IL-1beta gene expression in differentiating human keratinocyte cell lines in a time- and dose-dependent manner. Increases in prointerleukin-1beta (pIL-1beta) protein and IL-1beta steady state mRNA levels were observed in both SCC-12F and HaCaT cells following TCDD treatment. When pretreated with alpha-naphthoflavone, an AhR antagonist, TCDD-mediated increases in IL-1beta gene expression were attenuated, demonstrating for the first time that the environmental toxin, TCDD, can stimulate cytokine (IL-1beta) gene expression in an AhR-dependent manner. Nuclear run-on experiments were performed in SCC-12 cells to determine if the AhR-dependent increases in IL-1beta expression were due to transcriptional activation of the IL-1beta gene. Results showed high constitutive levels of IL-1beta transcriptional activity, however, TCDD treatment, which stimulated IL-1beta steady state mRNA levels, failed to potentiate IL-1beta transcription. Taken together, these results demonstrate that AhR-mediated IL-1beta regulation is occurring posttranscriptionally.

Photocontact dermatitis and chloracne: two major occupational and environmental skin diseases induced by different actions of halogenated chemicals

Among occupational and environmental disorders, contact or photocontact dermatitis and an acneiform eruption are two major skin disorders. Photocontact dermatitis was historically caused by various halogenated salicylanilides, while the acne is induced by halogenated aromatic hydrocarbons and thus called chloracne. Therefore, it should be noted that halogenated chemical compounds are important causative agents in the occupational and environmental medicine. In photocontact dermatitis, photoconjugation of epidermal cells with a photohaptenic halogenated chemical is the initial step. Langerhans cells serve as antigen-presenting cells and T cells sensitized by photoantigen-bearing Langerhans cells induce this photosensitivity. On the other hand, in chloracne, halogeneted hydrocarbons render keratinocytes of the outer root sheath and sebaceous duct hyperplastic. The dilated infundibulum of most hair follicles is then filled with comedone that consist of many accumulated layers of keratinized cells and sebum. Therefore, halogenated chemicals exhibit different actions, i.e. the induction of an immunologic consequence and the modulation of keratinocyte biology. These two conditions also provide good experimental models for investigating dermatology.

Environmental effects and skin disease

The skin is the largest organ in the body and one of its main functions is to protect the body from noxious substances, whether they are ultraviolet radiation, toxic chemicals or prolonged/repeated exposure to water. It is the level of exposure that determines if damage to the organism will result. The harm that can occur to the skin with sufficient exposure will be considered. Contact dermatitis, halogen acne, chemical depigmentation, connective tissue diseases and skin cancer are the conditions that will be covered in this chapter, as environmental exposure is important in their aetiologies. Systemic absorption will not be dealt with. Most environmental exposure to harmful substances will occur at work, but exposure may occur at home or during normal day-to-day activities.

Chloracne: histopathologic findings in one case

BACKGROUND

Chloracne is an acneiform eruption due to poisoning by halogenated aromatic compounds having a specific molecular shape. This condition is always a symptom of systemic poisoning by chemical chloracnegens and not just a cutaneous disorder.

METHODS

We have studied a patient with severe chloracne who showed cutaneous lesions involving mostly the face and the axillae.

RESULTS

Histopathologic study of the facial lesions demonstrated that almost every vellus hair follicle was involved, showing a dilated infundibulum filled by a keratotic plug. This keratotic material was mostly composed of orthokeratotic basket-weave basophilic corneocytes, namely infundibular keratin, although there were also some dilated infundibula containing eosinophilic laminated or granular sebum at their center. Small infundibular cysts were more numerous than comedones. Mature and well-developed sebaceous glands were seen at the base of many of the dilated infundibula and no squamous metaplasia of the sebaceous glands or ducts could be demonstrated. Hyperpigmentation of the lesions resulted from hyperproduction of melanin by a normal number of melanocytes along the basal layer of the epidermis and infundibular epithelium. Abundant melanin granules also impregnated the corneocytes of the infundibular plugs.

CONCLUSIONS

Our findings support the notion that tiny infundibular cysts rather than comedones represent the basic lesions of chloracne.

Punctate keratoderma-like lesions on the palms and soles in a patient with chloracne: a new clinical manifestation of dioxin intoxication?

We report what we believe to be a novel skin manifestation of dioxin intoxication. A 30-year-old woman with 2,3,7, 8-tetrachlorodibenzo-p-dioxin levels of 144,000 pg g-1 blood fat presented with severe chloracne that affected the entire integument. She also exhibited acral granuloma annulare-like lesions and distal onycholysis and, at a later time point, showed signs of hypertrichosis, as well as brownish-grey hyperpigmentation of the face. In addition, she developed punctate keratoderma-like lesions on the palms and soles. These lesions were negative for human papillomavirus and histologically characterized by cone-shaped hyperkeratoses invaginating, but not penetrating, into the dermis. Squamous syringometaplasia of the eccrine glands was observed in the immediate vicinity of these lesions. Both clinically and histologically these alterations are essentially indistinguishable from what is described as keratosis punctata palmaris et plantaris (KPPP). Although a fortuitous coincidence of chloracne and KPPP cannot be formally excluded, the possibility exists that in our patient toxic levels of dioxin were causally involved in this disorder of keratinization.

Blood lipid concentrations of dioxins and dibenzofurans causing chloracne

Chloracne is caused by exposure to certain halogenated polycyclic hydrocarbons such as polychlorinated dibenzodioxins (PCDDs) and dibenzofurans (PCDFs). In chronic exposure it is not known what level of intoxication, represented by the level in blood lipids, is sufficient to cause chloracne. Blood levels of the congeners of PCDD/Fs were determined in four groups of humans. One group had clinically visible chloracne due to exposure in a hexachlorobenzene workshop of a large chemical factory. A second group was exposed in the same workshop, but had no skin changes. There were two control groups: one non-exposed group of maintenance workers from the same chemical factory, and one group of healthy individuals living elsewhere. Blood levels were converted to toxicity equivalents of tetrachlorodibenzo-p-dioxin (TCDD). In the chloracne group blood levels in toxicity equivalents (TEQs) ranged from 1168 to 22,308 pg/g blood lipid. In the exposed without chloracne this ranged from 424 to 662 pg/g. It is concluded that the level to develop chloracne is between 650 and 1200 pg/g TEQ. The contribution of TCDD was rather small, and the main causative congeners were the hexachlorinated dibenzodioxins and dibenzofurans (HxCDD/Fs); lipid-based blood levels in absolute amounts that may cause chloracne are in the range of 2-3.5 ng/g HxCDD, and 2-5 ng/g HxCDF.

Serum dioxin, chloracne, and acne in veterans of Operation Ranch Hand

The possible relationship between exposure to Agent Orange and its contaminant, 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin), during the Vietnam War and chloracne was investigated. The index subjects were veterans of Operation Ranch Hand, the unit responsible for aerial herbicide spraying in Vietnam from 1962 to 1971. Other Air Force veterans who served in Southeast Asia during the same period, but who were not involved with spraying herbicides, served as comparisons. None of the Ranch Hand veterans were diagnosed with chloracne; therefore, we restricted our analyses to acne. We found no meaningful or consistent association between dioxin exposure and prevalence of acne without or with regard to anatomical location. These results suggested that exposure of Ranch Hand veterans to dioxin was insufficient for the production of chloracne or perhaps the exposure may have caused chloracne that resolved and was currently undetectable.

Dermatotoxicity of agricultural chemicals in the dorsal skin of hairless dogs

Dermatotoxicity of agricultural chemicals (ACs) with or without ultraviolet (UV) irradiation was histologically examined using hairless descendants of Mexican hairless dogs. ACs examined were pentachlorophenol sodium salt, 2,4-dichlorophenoxyacetic acid (DCPAA), Maneb, and Zineb. One day after cessation of the 7-day AC treatment, the skin treated with DCPPA and Maneb indicated only slight histological changes. The UV + AC-treated sites had as much pigmentation as the control sites. Fourteen days after cessation of treatment, dogs treated with Maneb showed marked reactions such as epidermal degeneration, vasodilation, and intradermal infiltration of inflammatory cells. These histological changes were more severe in the UV + AC-treated sites. Zineb induced comedones with well-developed pilosebaceous glands. These results suggest that hairless dogs may be useful laboratory animals for the investigation of dermatotoxicity of ACs in conjunction with UV irradiation.

Chloracne in the 1990s

BACKGROUND

Chloracne is a disease associated with toxicity of halogenated compounds used in some industrial processes. A patient affected by chloracne led us to study a total of nine cases from a single factory.

METHODS

We studied the clinical features of nine patients exposed chronically to chlorobenzenes. On all of them blood samples were drawn and biopsies of affected skin and liver were taken. Their work environment was visited and studied.

RESULTS

All nine patients were men and had polymorphic skin lesions, characterized mainly by comedones and cysts. They had chronic conjunctivitis and seven had cysts in the Meibomian glands. All of them had polyneuropathy and liver damage and seven had hypertriglyceridemia. Compounds known to cause chloracne were found in exceedingly high concentrations in the water used in the workplace.

CONCLUSIONS

Every patient exposed to halogenated compounds with the cutaneous manifestations of chloracne should be carefully investigated for systemic complications (such as ophthalmic, neuropathic, hepatic, and lipoprotein abnormalities).

Interactive effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin and retinoids on proliferation and differentiation in cultured human keratinocytes: quantification of cross-linked envelope formation

Dioxins are potent inducers of chloracne in humans. This skin aberration can be interpreted as an altered differentiation pattern of acinar sebaceous base cells and a change in the rate of terminal differentiation of the keratinocytes. We measured this rate induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in primary cultures of human keratinocytes. As parameters for differentiation, we quantified the 35S-methionine incorporation into cross-linked envelopes (revealing the total CLE biomass), as well as the number of microscopically visible CLEs. It was shown that TCDD is a very potent inducer of both CLE biomass and number with a half-maximal effect concentration (EC50) of 1.4 nM. CLE biomass was maximally increased 10-fold and the number of cells in culture producing a CLE was increased from 15% in control cultures to maximally 75% of the cells in TCDD-treated cultures. Both effects were Ca(2+)-dependent and increased with elevated cell density, being optimal in post-confluent cultures. Retinoic acid dose-dependently decreased the effect of 10(-8) M TCDD, 10(-6) M having a nearly complete antagonistic action. This interaction of retinoic acid with TCDD-induced differentiation was non-competitive. Retinol was equally potent as an antagonist of the TCDD-induced elevation of CLE formation as compared with retinoic acid. Retinyl palmitate and etretinate were not very effective as TCDD antagonists. Supplementation of hydrocortisone suppressed the TCDD-induced keratinocyte differentiation. It was concluded that CLE biomass quantification provides a reliable and sensitive parameter for keratinocyte differentiation. In this in vitro system it is shown that TCDD strongly induces a switch from proliferation to terminal differentiation and that this effect can be antagonized effectively by retinoic acid and retinol.

Follow-up of skin manifestations in Yu-Cheng children

We report an 11-year follow-up study on the dermatological manifestations of Yu-Cheng children born to mothers who were poisoned by polychlorinated biphenyl (PCB)-contaminated cooking oil between 1977 and 1979. Eighty-eight children born to these mothers, and 86 matched controls, were examined by one dermatologist. Chloracne scars were found in one patient, and there were nail abnormalities in about one-third of the exposed patients. Transverse grooves, irregular depressions, and koilonychia/nail flattening were significantly more frequent than in the control group, based on Fischer's exact test. This study indicates that in Yu-Cheng children the nail changes are the most persistent abnormality after PCB intoxication, and their occurrence may indicate developmental retardation of the fetal nail matrix. Such a finding might also suggest that PCBs remaining in the mother could exert an effect on nail growth in children born several years after the intoxication event.

Severe halogen acne due to a trifluoromethylpyrazole derivative and its resistance to isotretinoin

We report a case of severe chloracne, with systemic involvement, following occupational exposure to dihydrotrifluoromethylphenyl benzothiopyranopyrazolone, which, to our knowledge, has not been previously reported as a cause of chloracne. Aggressive drug treatment, including high-dose oral isotretinoin was of limited benefit in suppressing the disease activity.

Chloracne, palmoplantar keratoderma and localized scleroderma in a weed sprayer

The case of a 53-year-old man who developed chloracne, palmoplantar keratoderma and scleroderma after many years of exposure to a variety of chloracnegens is reported. Chloracne is a rare but important acneiform eruption associated with exposure to halogenated aromatic compounds used primarily in agriculture. However, to our knowledge, the association of palmoplantar keratoderma and scleroderma with exposure to chloracnegens has not been previously reported.

Chloracne--study of an outbreak with new clinical observations

A recent outbreak of chloracne in 17 workers is reported at a plant manufacturing dichloroaniline derivatives. Comedones developed 6-12 weeks after accidental exposure to the chloracnegenic contaminants and were present in every case. Cutaneous xerosis and a folliculitis, previously only rarely described as manifestations of chloracne, were noted in half the patients. The pathogenesis of these lesions is uncertain but may involve a disorder of keratinization.

Light cautery and EMLA in the treatment of chloracne lesions

We report six patients with chloracne, unresponsive to conventional therapy, whose lesions were cleared by treatment with EMLA (eutectic mixture of lignocaine [lidocaine] 25 mg/g and prilocaine 25 mg/g) topical anaesthesia and light cautery. To the best of our knowledge, this form of treatment for chloracne has not previously been reported.

Dowling-Degos' disease mimicking chloracne

We describe a patient with clinical features that resembled severe chloracne; however, histopathologic findings revealed a reticulated pigmented anomaly. Innumerable comedones, many cysts, acneiform scarring, and flexural and facial pigmentation were noted in this patient, who is a machinist. A serum test for polychlorinated biphenyl was negative, which eliminated a diagnosis of chloracne. The spectrum of clinical features of the histologically well-defined Dowling-Degos' disease is discussed; in this disease lesions can be flexural or acral and can appear as macules, comedones, or cysts.