Dermatitis does not belong to the name of a disease, but should be the category of a large group of skin diseases, such as eczema, psoriasis, nodular itchy rash and other symptoms, all belong to dermatitis. In contrast, urticaria is the name of a disease that is mainly caused by skin manifestations due to allergies against certain substances on the basis of autoimmune dysfunction, mainly manifested as pruritic red bumps and edematous bumps on the skin, caused by skin edema. The corresponding main allergens may be caused by medications, inhalants, such as dust, pollen, etc., or inhalants, such as eggs, milk, beef and mutton. Secondly, there are also contact substances, such as contact with external rubber-like substances, or hair dyes, fragrances and other substances, which in turn cause skin allergies. Urticaria is mainly manifested as edematous, itchy skin lesions, and may also occur in the mucous membranes of the body, for example, in the respiratory tract mucosa, causing chest tightness and shortness of breath. If it occurs in the mucosa of the gastrointestinal tract, it can cause abdominal pain and diarrhea. If a patient has tight breathing, chest tightness or abdominal pain or diarrhea, he or she needs to seek medical attention because anaphylaxis may occur.