As the saying goes, disease enters through the mouth. When you mention this disease, you may associate it with microorganisms and parasites of all shapes and sizes such as bacteria and viruses. For people with skin diseases, this disease may be some common foods that we all eat in our lives. If a food allergy occurs, it can cause a rash, itching, asthma, or severe abdominal pain, vomiting, diarrhea, or even shock, which can be life-threatening. Therefore, good control of the mouth to maintain and improve skin health is very important. The specific foods that should be avoided depend on the individual’s specific situation. Unfortunately, it is like looking for a needle in a haystack to find out exactly which food someone is allergic to, because many allergic people are not just allergic to one food, but often may be allergic to many foods, which we call polygenic allergies. What’s more, our allergic reactions sometimes change depending on age, body type, environment and climate, so it’s not practical to try to eliminate them one by one by skin testing, but there are also some false positives or false negatives, so it’s not a good choice. The most economical, easy and reliable method is still up to you. Typically, we use the food elimination method and the food documentation method to find allergens. The food elimination method is to eat light foods that you are known not to be allergic to for 3 weeks, and then add a food every 4-5 days to confirm which food caused the allergy. The food record method is to make a detailed record of the type and time of food eaten in relation to the occurrence of allergic symptoms, and to determine the allergen through analysis. It is generally important to pay attention to what you ate and drink in the 12-24 hours before the onset of symptoms. Patients with conditions like acne, seborrhea, seborrheic dermatitis, rosacea, and some infectious skin diseases should not consume too much sugar and fat. Because the occurrence of these diseases are mostly related to sugar metabolism and lipid metabolism, fatty and sugary food can aggravate the condition; certain pruritic skin diseases such as psoriasis, pruritus, etc., the exact cause of itching is not well understood, the intake of irritating food can stimulate the gustatory reflex arc, causing reactive vasodilatation congestion, skin redness, itching aggravation, therefore, such patients should avoid chili, onion, garlic, ginger, strong tea, coffee, etc. Photoreceptor dermatosis is often due to the consumption of mud snail, amaranth, rape, etc., and then the acute inflammatory reaction of the skin caused by sun exposure, patients should avoid the above-mentioned food; herpes-like dermatitis patients, avoid eating kelp, nori and other iodine-rich food; long-term use of corticosteroids in patients with dermatosis, to prohibit the consumption of pickled products, and change to a low-salt diet to reduce the side effects of hormone-induced water sodium retention. So what can dermatology patients eat in the end? 1, it is appropriate to eat foods rich in vitamin C, such as fresh vegetables and fruits; 2, it is appropriate to eat foods rich in calcium, such as beans and soy products, dairy and dairy products; 3, all patients with skin diseases related to nutritional deficiencies, must be supplemented with the lack of nutrients, such as dermatitis, digestive and neuropsychiatric symptoms as the main manifestation of pellagra patients, must be given high protein, rich in nicotinamide food, such as eggs, milk milk, meat, beans, peanuts, fresh green vegetables, etc.