Skin allergies on the face are mainly caused by drug factors, environmental factors or disease factors. 1. Drug factors: drugs that cause skin allergies mainly include antibiotics (such as penicillin), sedatives (such as atropine), herbs (such as ganoderma lucidum) and vaccines (such as rabies vaccine), and other biological agents; all of which can cause an abnormal immune response and lead to skin allergy symptoms on the face. 2. Environmental factors: excessive cold, excessive heat, excessive sun exposure, or contact with organic solvents, animal fur, etc., will also induce an abnormal immune response and symptoms of skin allergies. 3. Disease factors: Eczema, contact dermatitis or purpura and other diseases can also lead to an abnormal immune system response, which can also lead to the appearance of the above symptoms. It is recommended to consult a doctor for a clear diagnosis of skin allergies on the face, in order to avoid delays in the treatment of the disease.