The most common disease in dermatology. There is exogenous dermatitis that are the cause of some external factor (toxic, allergic and infectious) and endogenous (atopic dermatitis, seborrheic dermatitis, bromhidrosis, neurodermatitis, etc.). In the acute phase we have redness, swelling, bubbles and itching while in chronic condition the rash turns to dry, lipid. In the investigation of exogenous dermatitis, patch tests play an important role where we stick to the back of the sufferer several sticky allergens and read the result within 48-72h.