The causes of skin allergy can be roughly divided into internal causes and external causes, external causes. It is the factors that individuals are exposed to, such as food, use and external environment. For example, some people are allergic to peanut butter, shrimp and fish. Allergic to sunlight. Skin care products, toilet water, essential oil and medicinal ointment can also cause allergies. There are also allergies to formaldehyde, pollen and trees. Internal cause. That is, the immune dysfunction of the body, long-term anxiety, tension, fatigue, lack of sleep and stress will lead to immune dysfunction, or major mental shock, surgery, family changes and so on. Can lead to immune disorders and allergies. There are also visceral diseases, endocrine and metabolic system diseases are also one of the causes of allergies.