Erythrasma - A Red Herring in the Ongoing Epidemic of Tinea.

We describe the presentation of five adults with erythrasma, misdiagnosed as tinea and prescribed antifungal treatment which resulted in incomplete clearance. The lesions were restricted to axillary and/or inguinal folds. They were dry, brown macules with fine scaling. Except for one with moderate pruritus, they were asymptomatic. No fungal elements could be demonstrated in any of the patients in 10% KOH preparation. Gram stain revealed short gram-positive rods in varying proportions. All the patients showed a pink fluorescence on Wood's lamp examination. After treatment with topical clindamycin singly or in combination with oral azithromycin, there was complete clearance of the lesions leaving normal-appearing skin in three and residual hyperpigmentation in one. The overdiagnosis of tinea in the ongoing epidemic of dermatophytosis is a potential concern. Wood's lamp examination is very useful to confirm or exclude erythrasma.

Pure Cutaneous Rosai Dorfman Disease: An Uncommon Location for a Rare Histiocytic Proliferative Disorder.

RosaiDorfman disease (RDD) is a rare, self-limiting disease of uncertain etiology involving lymph nodes as well as extranodal sites. Isolated or pure cutaneous RDD (PCRDD) without lymph node involvement is very unusual accounting for only 3% of all described cases of RDD. The clinical features of PCRDD are quite different from RDD according to the literature on extranodal RDD, thereby emphasizing that PCRDD is a distinct clinical entity. Histopathology remains the gold standard for the diagnosis of both systemic and PCRDD with the presence of characteristic emperipolesis observed in histiocytes while immunohistochemistry (IHC) (S100, CD 68 positive, and CD 1a-negative) serves as a useful adjunct. We hereby report a case of a 36-year-old female who presented with a tender, indurated plaque on the left forearm with a clinical differential diagnosis of borderline tuberculoid leprosy/sarcoidosis and lupus vulgaris. However, on histopathology, a diagnosis of RDD was performed and confirmed on IHC. This case highlights the need to create awareness among young pathologists and clinicians about PCRDD to prevent overzealous treatment.

Role of contact allergens in pompholyx.

Fifty patients of both sexes with clinically suspected pompholyx were patch tested with the Indian Standard Patch Test Battery approved by the Contact & Occupational Dermatosis Forum of India (CODFI). Most of these patients were young adults between 20-39 years of age with a mean age of 30 years. The mean duration of symptoms was 4 years. The occupational profile of the patients included students (20%), housewives (16%), housewives engaged in farming (12%), labourers (12%), farmers (12%) and paramedical workers (6%). The miscellaneous group, including salesmen, teachers and photographers, accounted for the remaining 22%. The clinical patterns of presentation of pompholyx included cheiropompholyx (60%), cheiropompholyx and podopompholyx (36%) and podopompholyx alone (4%). Patch test analysis of these patients revealed that, out of the 50 subjects tested, 20 (40%) reacted to one or more allergens. Nickel sulphate was the commonest offending allergen (14%) followed by potassium dichromate and phenylene diamine and nitrofurazone (8% each), fragrance mix (6%) and cobalt chloride (4%), in descending order of frequency. Hence, patch testing may be considered for all patients with recurrent episodes of pompholyx as allergic contact dermatitis may be relatively common in such patients and the avoidance of offending allergens may be of substantial benefit to these patients.