Skin allergies may be related to eczema, urticaria and contact dermatitis. 1. Eczema: its cause is more complex, may be related to genetics, immune function and environmental factors, the patient’s skin will appear erythema, pimples, blisters and itching and other symptoms. 2. Urticaria: its causes are mostly related to food, drugs and infections, etc., and patients will have red spots of different sizes on their skin, wind masses, mostly accompanied by itching symptoms. 3. Contact dermatitis: its cause may be related to skin contact with exogenous irritants or allergic substances, such as animal, plant and chemical, etc., the patient’s skin will appear erythema, edema and pimples and other symptoms, often accompanied by itching. There are many causes of skin allergies, and it is recommended that patients seek medical examination to clarify the causes.