Approximately 10 per cent of patients with atopic dermatitis have clinical manifestations that are significantly affected by allergens. Food allergies appear to be more common in infants, while aeroallergens probably affect older children and adults more frequently. Patients who do not respond favorably to standard regimens of lubrication, topical corticosteroids, and antihistamines should be evaluated for allergies to foods and aeroallergens. Historical information, radioallergosorbent tests, and prick tests guide in the selection of allergens to be eliminated, but elimination and challenge tests are most useful in the determination of allergens that may affect atopoic dermatitis.