Foot eczema and footwear dermatitis: Role of patch test using Indian standard series and footwear series

Background and objectives: Foot eczema is a common complaint encountered in Dermatology outpatient department. Footwear dermatitis forms an important exogenous cause of foot eczema. Patch testing may help in identifying possible allergens causing footwear dermatitis and thus helps both the clinician and patient in prevention and treatment of foot eczema. The objective of this study was to study the clinical profile of foot eczema and to evaluate patch test results in these patients. Methods: 50 patients with foot eczema were included in the study and underwent patch testing with Indian standard series and footwear series. Patch test results were read at 48 hours and 96 hours using International Contact Dermatitis Research Group (ICDRG) guidelines. Results: Foot eczema was most common in 18-29 age group (48%), with a male:female ratio of 1.78:1. Office workers (50%), followed by students (24%) were the common occupational groups affected. Allergic contact dermatitis (60%), followed by discoid (10%) and forefoot eczema (10%) were the common morphological types. Parthenium (13.8%), diphenylguanidine (10.3%) and potassium dichromate (10.3%) were common allergens seen. Paraphenylenediamine (ppd) (33.3%) was the most common allergen in housewives, parthenium (28.6%) in farmers, mercaptobenzothiazole (22.2%) in students and diphenyl guanidine (16.1%) in office workers. Potassium dichromate showed highest male preponderance, whereas, ppd was more common in females. Nitrofurazone and neomycin were the common medicaments encountered. Conclusions: Both foot eczema and footwear dermatitis were more common in males and allergic contact dermatitis formed a large majority. Parthenium was the most common allergen identified by patch testing which reflects its rampant presence in India. Patch testing has a sensitivity of only 58.1% and specificity of 36.8%. Nevertheless, it may be used as valuable, safe additional tool to aid the clinician’s diagnosis and help in treatment of allergic contact dermatitis