Allergic dermatitis is a dermatological disease caused by various types of allergens. It may manifest as local redness, itching or rash. In pharmacies, you can buy over-the-counter ointments, creams or gels for use on the skin that contain antihistamines (e.g. dimetinden) or steroids (e.g. hydrocortisone) with strong antiallergic, antipruritic and anti-inflammatory properties.