Dermatitis refers to inflammatory skin diseases caused by a variety of factors. Pimple dermatitis is considered to be insect bite reaction, neurodermatitis, contact dermatitis and other diseases, which need to be treated according to the cause of the disease, including general treatment, medication and so on. 1. Insect bite reaction: also known as papular urticaria, it is a kind of red wind-bubble-like papular dermatosis. Patients can apply topical glycerite lotion, which can relieve itching. If the itching and rash are severe, oral antihistamines, such as loratadine and cetirizine, or topical glucocorticosteroids, such as dexamethasone, have anti-inflammatory and antipruritic effects. 2. Neurodermatitis: the lesions are flat papules, most of which are dense in pieces, accompanied by obvious itching. Patients should remove the triggers, avoid friction and scratching. Topical glucocorticoid drugs such as dexamethasone and hydrocortisone acetate can be used. 3. Contact dermatitis: manifested as erythema, swelling, pimples, etc., is a kind of inflammatory dermatosis caused by contact with external substances, the patient should look for triggers, avoid re-exposure. It can be treated with topical glucocorticoids, such as hydrocortisone and dexamethasone. For patients with papular dermatitis, they should go to the local regular hospitals, clarify the cause of the disease, cooperate with the doctor to standardize the treatment, and the medication should be prescribed by the doctor.