Dermatitis is a general term for a group of skin conditions that present as papules, erythema and itching. The broad term dermatitis also includes eczema with blisters and oozing. There are many causes and therefore many types of dermatitis, such as neurodermatitis due to friction and scratching, artificial dermatitis due to self-injury in psychiatric patients, stasis dermatitis due to varicose veins, radiation dermatitis due to exposure to radioactive rays, allergic dermatitis due to various routes of exposure to allergic substances, and so on. The most common of these is allergic dermatitis. There are many types of allergic dermatitis depending on the cause and clinical manifestations, such as drug allergic dermatitis, contact allergic dermatitis, photosensitivity dermatitis, genetic allergic dermatitis, and auto-sensitivity dermatitis. Allergic dermatitis generally occurs in allergic patients, and intrinsic allergic factors play a leading role in the development of allergic dermatitis. The instability of the intrinsic environment such as chronic digestive diseases, mental stress, insomnia, excessive fatigue, emotional changes and other mental changes, as well as infectious lesions, metabolic disorders and endocrine dysfunction, can trigger or aggravate the condition of atopic dermatitis. There are also many external factors that contribute to the occurrence of allergic dermatitis. These include factors such as diet, inhalants, climate, and exposure to allergens. Among them, seafood, spicy food, wine, inhalation of pollen, dust mites, cold weather, exposure to chemicals, soaps, detergents, etc. are the most common causes and triggers of allergic dermatitis. Because of such complex causes, allergic dermatitis is prone to recurrent attacks due to the intertwining of numerous etiological and triggering factors.