Irritant and allergic contact dermatitis are commonly seen in patients complaining about itching, burning and irritation in the vulvar area. Irritation often precedes allergic sensitization. Clinically, irritant and allergic contact dermatitis can be difficult to distinguish. Diagnosis is made by history, clinical investigation and patch testing. Recommended patch test series are the standard series, a medicament series, the patient's own topical medicaments, popular remedies and other suspected products. A skin biopsy may be useful to establish the diagnosis of contact dermatitis, but it is usually not helpful for the differential diagnosis between irritant and allergic dermatitis.