Schwann cells as underestimated, major players in human skin physiology and pathology.

Schwann cells (SCs) have long been recognized for their ability to support repair and promote axon regeneration following injury to the peripheral nervous system. In response to nerve injury, they rapidly dedifferentiate into a precursor-like state, secrete an array of inflammatory mediators and growth factors, proliferate, undergo epithelial-to-mesenchymal-like transformation to facilitate migration, phagocytose cellular debris and remodel the extracellular environment to promote regeneration of axons through the site of injury. However, even though a cutaneous role for SCs is becoming increasingly recognized, we argue in this Viewpoint essay that the likely complex functions of SCs in skin physiology and pathology beyond skin sensation and nerve repair deserve more attention and systemic research than they have received so far. For example, SCs promote wound healing, disseminate infection in leprosy, support the growth of neurofibromas/schwannomas and facilitate/accelerate the growth and invasion of melanoma. Despite representing a major dermal cell population, comparatively little is still known about the role of SCs in other dermatoses. To quintessentially illustrate the opportunities that promise to arise from a new skin research focus on SCs, we focus on two dermatoses that are not traditionally associated with SCs, that is, psoriasis and atopic dermatitis (AD), since both show distinct SC changes along with continuous nerve fibre degeneration and regeneration, and an impact of denervation on skin lesions. Specifically, we critically discuss the hypothesis that repeated activation of the SC repair programme occurs in and contributes to psoriasis and AD and delineate experimental approaches how to probe this clinically relevant hypothesis.

Methicillin-resistant Staphylococcus aureus colonization and disease severity in atopic dermatitis: a cross-sectional study from South India.

BACKGROUND: Colonization by methicillin-resistant Staphylococcus aureus (MRSA) in atopic dermatitis is little studied but has therapeutic implications. It may have a role in disease severity given the additional virulence factors associated. AIMS: Our aims were to record the proportion of patients with MRSA colonization in atopic dermatitis and to ascertain if any association exists between MRSA colonization and disease severity. METHODS: An observational cross-sectional study involving children aged≤12 years with atopic dermatitis attending the outpatient department of Government Medical College, Kottayam was conducted. Socio-demographic data, exacerbating factors and risk factors for hospital care-associated MRSA were documented. Extent of atopic dermatitis was recorded using a standardized scale (Eczema Area Severity Index, EASI). Skin swabs were taken from anterior nares and the worst affected atopic dermatitis sites for culture and sensitivity. RESULTS: Of the 119 subjects recruited during the study period (November 2009-April 2011), Staphylococcus aureus was isolated from 110 (92.4%) patients and MRSA from 30 (25.21%) patients. A total of 18 patients with MRSA had risk factors for healthcare associated-MRSA. The patients whose cultures grew MRSA were found to have significantly higher EASI score when compared to those patients colonized with methicillin sensitive Staphylococcus aureus (P < 0.01). Presence of Staphylococcus aureus, early age of onset, presence of food allergies, seasonal exacerbation and inadequate breastfeeding did not seem to influence disease severity. CONCLUSIONS: There is a high degree of prevalence of MRSA (25.2%) in atopic dermatitis and presence of MRSA is associated with increased disease severity. Further studies are needed to validate these findings.

Intranasally administered antigen 85B gene vaccine in non-replicating human Parainfluenza type 2 virus vector ameliorates mouse atopic dermatitis.

Atopic dermatitis (AD) is a refractory and recurrent inflammatory skin disease. Various factors including heredity, environmental agent, innate and acquired immunity, and skin barrier function participate in the pathogenesis of AD. T -helper (Th) 2-dominant immunological milieu has been suggested in the acute phase of AD. Antigen 85B (Ag85B) is a 30-kDa secretory protein well conserved in Mycobacterium species. Ag85B has strong Th1-type cytokine inducing activity, and is expected to ameliorate Th2 condition in allergic disease. To perform Ag85B function in vivo, effective and less invasive vaccination method is required. Recently, we have established a novel functional virus vector; recombinant human parainfluenza type 2 virus vector (rhPIV2): highly expressive, replication-deficient, and very low-pathogenic vector. In this study, we investigated the efficacy of rhPIV2 engineered to express Ag85B (rhPIV2/Ag85B) in a mouse AD model induced by repeated oxazolone (OX) challenge. Ear swelling, dermal cell infiltrations and serum IgE level were significantly suppressed in the rhPIV2/Ag85B treated mouse group accompanied with elevated IFN-γ and IL-10 mRNA expressions, and suppressed IL-4, TNF-α and MIP-2 mRNA expressions. The treated mice showed no clinical symptom of croup or systemic adverse reactions. The respiratory tract epithelium captured rhPIV2 effectively without remarkable cytotoxic effects. These results suggested that rhPIV2/Ag85B might be a potent therapeutic tool to control allergic disorders.

Terra firma-forme dermatosis.

Terra firma-forme dermatosis is characterized by 'dirty' brown-grey cutaneous patches and plaques that can simply be eradicated by forceful swabbing with alcohol pads. The pathogenesis has been attributed to abnormal and delayed keratinization. Although affected patients present with typical lesions, the disorder is not well-known by dermatologists. In this report, we describe two patients with terra firma-forme dermatosis in the setting of xerosis cutis and atopic dermatitis. From a clinical point of view, we lay emphasis on its unique expression and diagnosis/treatment. From a histological perspective, we highlight its resemblance to dermatosis neglecta and speculate on the role of 'neglect' in a patient with seemingly adequate hygiene. The role of urea containing emollients in the development of this disorder remains to be determined.

Hand eczema: correlation of morphologic patterns, atopy, contact sensitization and disease severity.

BACKGROUND: Hand eczema is a common distressing condition aggravated by a number of endogenous and exogenous factors. Various morphological forms of hand eczema have been described, but categorization into one of them is not always possible. AIMS: To study the morphological patterns of hand eczema, relationship of atopy with hand eczema, and the implications of contact sensitization with respect to severity and diagnosis of hand eczema. METHODS: Hundred consecutive patients of hand eczema attending the contact dermatitis clinic of the institute were recruited over a two year period from 2004-05. Objective assessment was done using hand eczema severity index (HECSI) and all the patients were patch tested using Indian standard series. RESULTS: Unspecified type of hand eczema with no definite morphologic picture was seen in 62% followed by pompholyx in 14%. Hand eczema severity was not found to be statistically associated with age, sex, and atopic status of the patient. Positive patch test to one or more allergen was present in 65% of patients. The most common allergens were potassium dichromate (25%), fragrance mix (16%), nickel sulphate (14%), and PPD (13%). There was no significant correlation between patch test positivity and hand eczema severity or atopic status of the patient. Among the morphological patterns pompholyx was strongly associated with an atopic status (P=0.004). CONCLUSIONS: Hand eczema was seen twice more commonly in men. Atopic and non-atopic patients of hand eczema had no difference in the severity of disease. Contact sensitivity to different allergens did not correlate with increased eczema severity.

Administration of Ag85B showed therapeutic effects to Th2-type cytokine-mediated acute phase atopic dermatitis by inducing regulatory T cells.

Increase in the number of patients with atopic dermatitis (AD) has been recently reported. T helper (Th) cells that infiltrate AD skin lesions are Th2-type dominant; reduced exposure to environmental Th1-cytokine-inducing microbes is believed to contribute to the increased number of AD patients. Regulatory type immune responses have been also associated with the occurrence of AD. It has been reported that antigen 85B (Ag85B) purified from mycobacteria is a potent inducer of Th1-type immune response in mice as well as in humans. In this study, we have examined the effect of plasmid DNA encoding Ag85B derived from Mycobacterium kansasii on AD skin lesions induced by oxazolone (OX) application. Th2-cytokine mediated mouse AD model with immediate type response followed by a late phase reaction was developed by repeated applications of low-dose OX to sensitized mice. Mice were immunized with plasmid DNA encoding cDNA of Ag85B before OX sensitization or during repeated elicitation phase. Both therapies were associated with significant suppression of immediate type response, clinical appearance, dermal cell infiltration, reduced IL-4 production, and augmented IFN-gamma mRNA expression compared to placebo-treated mice. Additionally, increased number of Foxp3(+) regulatory T cells were observed in the skin sections in Ag85B treated mice. The results of this study suggest that Ag85B DNA vaccine is a potential therapy for Th2 type dermatitis.

Evening primrose oil is effective in atopic dermatitis: a randomized placebo-controlled trial.

BACKGROUND: Atopic dermatitis (AD) is a chronic, relapsing, itchy dermatosis of multifactorial origin, which commonly starts in childhood. Defective metabolism of essential fatty acids leading to relative dominance of pro-inflammatory prostaglandins (PGE2 and PGF2) has been reported as an important factor in the pathogenesis of AD. Evening primrose oil (EPO) as a source of gamma-linolenic acid (GLA) has been of interest in the management of AD. AIM: To evaluate the efficacy and safety of EPO in atopic dermatitis in our patients. METHODS: Consecutive new out-patient department (OPD) patients of a referral hospital in Kolkata clinically diagnosed as having AD were randomly allocated to two groups. To the first group, evening primrose oil was supplied as 500-mg oval clear unmarked capsules, while placebo capsules identical in appearance and containing 300 mg of sunflower oil were given to the other group. Treatment continued for a period of 5 months. With pre-designed scoring system (based on four major parameters: extent, intensity, itching, and dryness), clinical evaluation was done at baseline and subsequent monthly visits. Data of the first 25 patients from each group who completed the 5 months of trial were compiled and analyzed. RESULTS: At the end of the fifth month, 24 (96%) patients of EPO group and 8 (32%) patients of placebo group showed improvement. There was significant difference in outcome of treatment between two groups (P<0.00001). No significant adverse effect was reported by any patient/guardian at any point of assessment. CONCLUSION: Evening primrose oil is a safe and effective medicine in management of AD. However, since not all researchers across the world have found the same good result, further large trials on Indian patients are needed.

Atopic patch testing.

BACKGROUND: Atopic dermatitis is a major problem among the urban population and it can be aggravated or triggered by various allergens. Atopic patch test can be used as a diagnostic tool in characterizing patients with allergen triggered atopic dermatitis. AIMS: 1. Patch testing to reproduce an eczematous reaction by applying prick test allergens under occlusion on intact skin. 2. To find the allergen associated with atopic dermatitis. 3. To find the specific allergen which causes or exacerbates atopic dermatitis in a given subject. METHODS: Seventy five subjects with atopic dermatitis were included in our study and patch tests using prick test allergens were applied to the back. Reading was done after 48 and 72 hours RESULTS: Out of the 75 subjects tested, 47% showed positive reactions, parthenium accounted for 42% of all positive reactions. CONCLUSIONS: Epicutaneous application of prick test antigen on intact skin can produce a reaction. Parthenium is commonest allergen in Bangalore. Counselling based on patch test reports may help to reduce morbidity and improve quality of life.

Dermatoses do pavilhäo auricular / External ear dermatosis

Apresentamos uma atualizaçäo sobre as dermatoses que ocorrem no pavilhäo auricular. Propomos uma classificaçäo em sete grupos e realizamos uma sucinta descriçäo clínica de cada uma das 84 entidades catalogadas, de forma didática, com a finalidade de auxiliar o médico, sobretudo o clínico geral, o dermatologista e o otorrinolaringologista, no diagnóstico de tais patologias.