RESUMEN
INTRODUCTION: Foot eczema is a common complaint encountered by skin allergists. OBJECTIVE: To study a series of patients with foot eczema who underwent patch testing and describe their demographic profile, diagnoses, and the main allergens involved. MATERIAL AND METHODS: Cross-sectional observational study of all patients tested with the standard Spanish patch test series at a dermatology department over a period of 13 years (2004-2016). We studied patch test results and definitive diagnoses by comparing different subgroups of patients with foot eczema. RESULTS: Of the 3,265 patients included in the study, 308 (9.4%) had foot eczema, 176 (57.9%) had foot eczema only and 132 (42.1%) had concomitant foot and hand eczema. Positive patch test results were more common in patients with foot eczema only (positivity rate of 61.5% vs. 53.4% for foot and hand eczema). In the subgroup of patients with concomitant foot and hand involvement, patients aged under 18 years had a lower rate of positive results (51.3% vs. 64.6% for patients >18 years). Potassium dichromate was the most common allergen with current relevance in all subgroups. The main diagnosis in patients with foot involvement only was allergic contact dermatitis (49.1%). In the subgroup of patients with concomitant hand and foot eczema, the main diagnoses were psoriasis in adults (33.6%) and atopic dermatitis in patients aged under 18 years (60.0%). CONCLUSION: Patch tests are a very useful diagnostic tool for patients with foot eczema with or without concomitant hand involvement.