Dyshidrosis: Epidemiology, Clinical Characteristics, and Therapy

Differential diagnosis of contact dermatitis: A practical-approach review by the EADV Task Force on contact dermatitis

The diagnosis of eczema ('dermatitis') is mostly clinical and depends on the clinical history and exploratory objective findings (primary lesions, patterns). Contact dermatitis remains as an important condition in the group of eczematous disorders, with important socioeconomic and occupational relevance. Although irritant and allergic contact dermatitis have a different pathogenesis, both are characterized by a rather typical morphology, are triggered by external factors and tend to occur primarily in the area of contact with the exogenous agent. In addition, allergic and irritant dermatitis may also co-exist. The importance of diagnosing contact dermatitis, especially when allergic in nature, is both due to the possibility of avoiding the trigger, and due to its role in aggravating other skin conditions. Nevertheless, the heterogeneity of clinical presentations in daily practice may pose an important challenge for the suspicion and correct diagnosis of contact dermatitis. Furthermore, other conditions, with different pathogenesis and treatment, may clinically simulate contact dermatitis. The Task Force aims to conduct a review of the unifying clinical features of contact dermatitis and characterize its main clinical phenotypes, and its simulators, in order to contribute to an early suspicion or recognition of contact dermatitis and enable a correct differential diagnosis.

Molecular and Physiological Functions of PACAP in Sweat Secretion

Sweat plays a critical role in human body, including thermoregulation and the maintenance of the skin environment and health. Hyperhidrosis and anhidrosis are caused by abnormalities in sweat secretion, resulting in severe skin conditions (pruritus and erythema). Bioactive peptide and pituitary adenylate cyclase-activating polypeptide (PACAP) was isolated and identified to activate adenylate cyclase in pituitary cells. Recently, it was reported that PACAP increases sweat secretion via PAC1R in mice and promotes the translocation of AQP5 to the cell membrane through increasing intracellular [Ca²⁺] via PAC1R in NCL-SG3 cells. However, intracellular signaling mechanisms by PACAP are poorly clarified. Here, we used PAC1R knockout (KO) mice and wild-type (WT) mice to observe changes in AQP5 localization and gene expression in sweat glands by PACAP treatment. Immunohistochemistry revealed that PACAP promoted the translocation of AQP5 to the lumen side in the eccrine gland via PAC1R. Furthermore, PACAP up-regulated the expression of genes (Ptgs2, Kcnn2, Cacna1s) involved in sweat secretion in WT mice. Moreover, PACAP treatment was found to down-regulate the Chrna1 gene expression in PAC1R KO mice. These genes were found to be involved in multiple pathways related to sweating. Our data provide a solid basis for future research initiatives in order to develop new therapies to treat sweating disorders.

Primary Varicella or Herpes Zoster? An Educational Case Report From the Primary Care Clinic

Varicella-zoster virus is a pathogenic virus that can present itself as a primary infection or secondary infection, also known as herpes zoster. Recently, there has been a re-emergence of this vaccine-preventable disease due to gaps in vaccination. Primary varicella in immunocompetent adults is highly uncommon, and it could result in severe complications within this population. Given this delicate scenario, family physicians should be well trained to recognize the characteristic cutaneous lesions of varicella and dictate adequate management for these patients to obtain the best possible outcome and prevent life-threatening complications.

We present the case of a 43-year-old immunocompetent woman with the onset of a generalized pruritic dermatosis characterized primarily by the presence of macules, vesicles, and crusts. The patients' lesions were compatible with primary varicella, and serological studies confirmed the diagnosis. Given the absence of acute complications in this individual, supportive treatment and close follow-up were the therapeutic modalities. This article focuses on the educational discussion of the primary differential diagnosis, evaluation for possible complications, and management of this uncommon clinical scenario. We also reinforce the importance of immunization in preventing re-emergent diseases as a critical element within primary care management.

Effect of PACAP on sweat secretion by immortalized human sweat gland cells

The process of sweating plays an important role in the human body, including thermoregulation and maintenance of the environment and health of the skin. It is known that the conditions of hyperhidrosis and anhidrosis are caused by abnormalities in sweat secretion and can result in severe skin conditions such as pruritus and erythema, which significantly reduce the patient's quality of life. However, there are many aspects of the signaling mechanisms in the process of sweating that have not been clarified, and no effective therapies or therapeutic agents have yet been discovered. Previously, it was reported that pituitary adenylate cyclase-activating polypeptide (PACAP) promotes sweating, but details of the underlying mechanism has not been clarified. We used immortalized human eccrine gland cells (NCL-SG3 cell) to investigate how sweat secretion is induced by PACAP. Intracellular Ca²⁺ levels were increased in these cells following their exposure to physiological concentrations of PACAP. Intracellular Ca²⁺ was not elevated when cells were concomitantly treated with PA-8, a specific PAC1-R antagonist, suggesting that PAC1-R is involved in the elevation of intracellular Ca²⁺ levels in response to PACAP treatment. Furthermore, immunocytochemistry experiments showed that aquaporin-5 was translocated from the cytoplasm to the cell membrane by PACAP. These results suggest that PACAP acts on eccrine sweat glands to promote sweat secretion by translocation of aquaporin-5 to the cell membrane in response to increased levels of intracellular Ca²⁺. These findings also provide a solid basis for future research initiatives to develop new therapies to treat sweating disorders.

Characterizing demographics and cost of care for dyshidrotic eczema

BACKGROUND

Dyshidrotic eczema (DE) is a common form of eczema affecting the hands, feet, or both areas. To date, there has been little research examining demographics and cost burden associated with this disease.

OBJECTIVE

This study seeks to characterize the demographics of patients affected and the direct costs of care associated with DE.

METHODS

This is a retrospective analysis utilizing insurance claim information from IBM MarketScan. Pertinent data including demographic information, healthcare provider type, medications prescribed, and average cost of care were identified using the ICD 10 code L30.1 for DE for the year 2018.

RESULTS

In 2018, 34 932 patients filed claims for DE, with 61% female and an average age of 37 years at first diagnosis. DE was mostly seen in employees from the service industry and the manufacturing of durable goods. The total annual direct cost was US $11 738 985. Average annual costs, however, did vary based on type of treating healthcare provider, level of care, and medications prescribed.

CONCLUSIONS

Patients with DE can face an economic burden due to their disease and providers should aim to recognize this disease and its treatments to minimize healthcare costs for patients and improve quality of life.

MrgprC11+ sensory neurons mediate glabrous skin itch

Itch arising from glabrous skin (palms and soles) has attracted limited attention within the field due to the lack of methodology. This is despite glabrous itch arising from many medical conditions such as plantar and palmar psoriasis, dyshidrosis, and cholestasis. Therefore, we developed a mouse glabrous skin behavioral assay to investigate the contribution of three previously identified pruriceptive neurons in glabrous skin itch. Our results show that MrgprA3⁺ and MrgprD⁺ neurons, although key mediators for hairy skin itch, do not play important roles in glabrous skin itch, demonstrating a mechanistic difference in itch sensation between hairy and glabrous skin. We found that MrgprC11⁺ neurons are the major mediators for glabrous skin itch. Activation of MrgprC11⁺ neurons induced glabrous skin itch, while ablation of MrgprC11⁺ neurons reduced both acute and chronic glabrous skin itch. Our study provides insights into the mechanisms of itch and opens up new avenues for future glabrous skin itch research.

Dyshidrotic Eczema: A Common Cause of Palmar Dermatitis

Dyshidrotic eczema (DE) or acute palmoplantar eczema is a common cause of hand and foot dermatitis in adults. It is a recurrent vesicular eruption affecting the soles, palms, or both. It is very pruriginous and generally appears suddenly. It creates vesicles that, on physical examination, can look similar to "tapioca pudding", which is the characteristic clinical feature of this disorder. It is more common in young adults and affects men and women equally. In this report, we present the case of a 56-year-old man with no relevant past medical history who presented to the hospital with vesicular lesions in his hands and maculopapular lesions in his arms and legs. The patient had characteristic lesions in his right hand consistent with DE and negative workup for bullous pemphigoid, scabies, and bacterial, fungal, and viral infections.

Diagnosis and Treatment Options for Inflammatory Skin Conditions of the Lower Extremity

The lower extremity presents several challenges from a dermatologic standpoint: there are different anatomic areas that not only vary from a stratum corneum thickness and histologic standpoint but are also subject to trauma that is unique (shoe gear, gait cycle). Attention to appropriate diagnosis and management is always warranted but should be especially vigilant to those treating issues of the lower extremity. This article reviews diagnosis and treatment of the most common skin and nail conditions of the foot and ankle.

Clinical profile of recurrent vesicular palmoplantar dermatitis in children and adolescents

BACKGROUND

Previously known as dyshidrosis, recurrent vesicular palmoplantar dermatitis (RVPD) is presented as severe eruption of nonerythematous, symmetrical vesicles or bullae located along the lateral sides of fingers, on the palmar or plantar areas, and developing into a chronic and recurrent condition. Although very frequently observed on the hands, there are no specific studies about such eczema in children and adolescents.

OBJECTIVES

To report on the RVPD clinical profile in children and adolescents, and monitor the association of RVPD with seasonal variations, hyperhidrosis, atopy and nickel sulfate.

MATERIALS AND METHODS

Eighteen patients affected by RVPD were submitted to clinical and laboratory assessment through anamnesis, physical exam, mycological exam, patch test, complete blood count and serum IgE levels.

RESULTS

Seven patients (38.9%) reported increased frequency of eruptions during the summer months; 12 patients (66.7%) presented hyperhidrosis; in 14 cases (77.8%), atopic factors were determined; reaction to nickel sulfate was positive in three patients (16.7%).

CONCLUSION

RVPD onset may occur at an early age, developing into a chronic and recurrent infection. Hyperhidrosis and atopic status was established in the clinical profile and no connection between nickel sulfate and RVPD was observed.

Overexpression of AQP3 and AQP10 in the skin exacerbates psoriasiform acanthosis

We previously observed that aquaporin-3 and aquaporin-10 are upregulated in the epidermis of hand dermatitis patients (Med. Hypotheses, 84, 2015, 498). To address the functional relevance of this upregulation, we overexpressed AQP3/AQP10 in mice using the human K1 promoter. Combining imiquimod with detergent-containing water challenge, a common trigger in hand and other dermatitis, resulted in an increase in acanthosis in mice overexpressing AQP3 or AQP3 and AQP10. Aquaporin overexpression also drove a trend towards greater weight loss in these animals. These data support a role for cutaneous aquaporins in the pathogenesis of dermatitis and as a potential target in their treatment.

Vesicular Hand Dermatitis in a Child: Allergy to Methylisothiazolinone

A 7-year-old girl presented with a history of vesicular hand dermatitis that only partially improved with the use of steroids. Patch testing revealed a 1+ reaction to 0.2% aqueous methylisothiazolinone (MI) and 0.01% aqueous methylchloroisothazolinone/methylisothiazolinone (MCI/MI). Dyshidrosiform hand dermatitis is rare in children younger than 10 years of age, and this pattern has not been reported with MCI/MI allergy.

Phenome-wide association study maps new diseases to the human major histocompatibility complex region

BACKGROUND

Over 160 disease phenotypes have been mapped to the major histocompatibility complex (MHC) region on chromosome 6 by genome-wide association study (GWAS), suggesting that the MHC region as a whole may be involved in the aetiology of many phenotypes, including unstudied diseases. The phenome-wide association study (PheWAS), a powerful and complementary approach to GWAS, has demonstrated its ability to discover and rediscover genetic associations. The objective of this study is to comprehensively investigate the MHC region by PheWAS to identify new phenotypes mapped to this genetically important region.

METHODS

In the current study, we systematically explored the MHC region using PheWAS to associate 2692 MHC-linked variants (minor allele frequency ≥0.01) with 6221 phenotypes in a cohort of 7481 subjects from the Marshfield Clinic Personalized Medicine Research Project.

RESULTS

Findings showed that expected associations previously identified by GWAS could be identified by PheWAS (eg, psoriasis, ankylosing spondylitis, type I diabetes and coeliac disease) with some having strong cross-phenotype associations potentially driven by pleiotropic effects. Importantly, novel associations with eight diseases not previously assessed by GWAS (eg, lichen planus) were also identified and replicated in an independent population. Many of these associated diseases appear to be immune-related disorders. Further assessment of these diseases in 16 484 Marshfield Clinic twins suggests that some of these diseases, including lichen planus, may have genetic aetiologies.

CONCLUSIONS

These results demonstrate that the PheWAS approach is a powerful and novel method to discover SNP-disease associations, and is ideal when characterising cross-phenotype associations, and further emphasise the importance of the MHC region in human health and disease.

Hand dermatitis: a review of clinical features, prevention and treatment

Hand dermatitis is a socially significant health problem. This review provides a discussion on the clinical features and patterns as well as the differential diagnosis of hand dermatitis, because these are essential for proper diagnosis in clinical practice. The morphology, however, is poorly related to the etiology in chronic cases. In all cases of chronic hand dermatitis, a full diagnostic examination should be undertaken and the etiology should be clarified and addressed in the treatment concept, instead of just moving directly from a morphological diagnosis to therapy. Preventive measures should be included in the treatment concept according to etiology. A stepwise approach for escalating therapy is advised, including basic topical therapy, topical corticosteroids, calcineurin inhibitors, as well as phototherapy and systemic therapy with corticosteroids, alitretinoin, cyclosporine, methotrexate, azathioprine, and others.

A Severe Case of Recalcitrant Pompholyx

BACKGROUND

Pompholyx is an inflammatory vesiculobullous skin disease of the hands and feet belonging to the spectrum of eczema.

OBJECTIVE

To report a severe case of pompholyx, its clinical presentation, and its management.

METHODS

A medical chart review was conducted on a patient with this condition.

RESULTS

The patient was patch tested according to the North American Contact Dermatitis Group (NACDG) Standard Screening Series, and results were negative. In the past, she was treated with corticosteroid creams as well as narrow band ultraviolet B (UVB), and Psoralen ultraviolet A (PUVA) therapies, and none were beneficial. When the frequency of the episodes increased, methotrexate was introduced but failed to control the condition. Next, mycophenolate mofetil was started and gradually increased to 3.5 g daily along with a separate trial of radiotherapy with marked success.

CONCLUSION

Pompholyx can be challenging to manage, and treatment can involve an assortment of therapies over a prolonged period of time.

The key role of aquaporin 3 and aquaporin 10 in the pathogenesis of pompholyx

Pompholyx remains a chronic skin affliction without a compelling pathophysiological explanation. The disease is characterized by the sudden onset of vesicles exclusively in the palms and soles which generally resolves. However, the disease may progress and the vesicles may expand and fuse; with chronicity there is deep fissuring. Multiple therapeutic approaches are available, but the disease is often resistant to conventional treatments. Currently, oral alitretinoin is used for patients with resistant chronic disease; however, this therapy is only approved for use in the UK, Europe and Canada. In this paper we wish to put forward a hypothesis: exposure to water and the subsequent steep osmotic gradient imbalance are key factors driving skin dehydration seen in pompholyx patients once the disease becomes chronic. The mechanistic explanation for the epidermal fissuring might lie in the over-expression across the mid and upper epidermis, including the stratum corneum, of two water/glycerol channel proteins aquaporin 3 and aquaporin 10, expressed in the keratinocytes of afflicted pompholyx patients. The over-expression of these two aquaporins may bridge the abundantly hydrated dermis and basal epidermis to the outer environment allowing cutaneous water and glycerol to flow outward. The beneficial effects reported in alitretinoin-treated patients with chronic hand eczemas may be due potential regulation of aquaporin 3 and aquaporin 10 by alitretinoin.

A systematic approach to systemic contact dermatitis and symmetric drug-related intertriginous and flexural exanthema (SDRIFE): a closer look at these conditions and an approach to intertriginous eruptions

Systemic contact dermatitis is a condition that occurs when an individual sensitized to a contact allergen is exposed to that same allergen or a cross-reacting molecule through a systemic route. Systemic exposure to allergens can include transcutaneous, transmucosal, oral, intravenous, intramuscular, and inhalational routes. Baboon syndrome is perhaps the most recognizable form of systemic contact dermatitis, presenting with diffuse, well demarcated erythema of the buttocks, upper inner thighs, and axillae. Other forms of systemic contact dermatitis include dermatitis at sites of previous exposure to the allergen such as at a previous site of dermatitis or at sites of previous positive patch tests, dyshidrotic hand eczema, flexural dermatitis, exanthematous rash, erythroderma, and vasculitis-like lesions. The most common causes of systemic contact dermatitis consist of three groups of allergens: (i) metals including mercury, nickel, and gold; (ii) medications including aminoglycoside antibacterials, corticosteroids, and aminophylline; and (iii) plants and herbal products including the Compositae and Anacardiaceae plant families and Balsam of Peru. Baboon syndrome caused by systemic medications without a known history of previous cutaneous sensitization in the patient has been termed drug-related baboon syndrome (DRBS) or symmetric drug-related intertriginous and flexural exanthema (SDRIFE). Criteria for SDRIFE include exposure to systemic drug at first or repeated dose, erythema of the gluteal/perianal area and/or V-shaped erythema of the inguinal area, involvement of at least one other intertriginous localization, symmetry of affected areas, and absence of systemic toxicity. The most common causes are aminopenicillins, β-lactam antibacterials, and certain chemotherapeutic agents, though the list of etiologic agents continues to grow. Baboon syndrome and SDRIFE should be strongly considered in a patient presenting with a symmetric intertriginous eruption involving multiple body folds. With the knowledge of the most frequent causes of these conditions, a detailed history and review of exposures will guide the clinician in the search for the most likely etiologic agent.