Erythema on the neck, which refers to the appearance of red patches on the skin in the neck area, may be caused by urticaria, lupus erythematosus, contact dermatitis and so on. 1. Urticaria: related to infection, food, drug allergies and other factors, causing winds, erythema, resulting in localized erythema, usually accompanied by significant itching. 2. Lupus erythematosus: Lupus erythematosus is an autoimmune disease, mainly manifested as butterfly-shaped erythema on the skin. It usually occurs on the face, but can also occur in other exposed parts of the body. 3. Contact dermatitis: contact dermatitis is mainly divided into irritant contact dermatitis and allergic contact dermatitis. Such as wearing necklaces, contact with suspicious drugs, metal elements, organic solvents, etc., may lead to localized skin damage, such as skin redness, itching, swelling, burning-like pain and so on. The appearance of erythema on the neck, it is recommended to timely dermatology consultation, please doctor for diagnosis, combined with the doctor’s advice standardized treatment.