Seborrheic dermatitis is not uncommon in the axillary fossa. Corresponding symptoms in other favourite areas of this common dermatosis help in diagnostics. The main differential diagnoses are erythrasma and candida infection. Flexural psoriasis shares the clinical features with seborrheic dermatitis. Combination therapy with a mild corticoid and an azole antifungal eases the problem of reaching a definite diagnosis.