When it comes to allergies, many people associate them with wind bumps on the skin after eating fish, shrimp and seafood, and redness and rashes on the skin after contact with certain substances, but in fact these are just some manifestations of allergic diseases on the skin. Allergy, known as metaplasia in academic circles, is an abnormal reaction of the body’s immune system to one or more substances, so allergic disease is a systemic disease that occurs mainly at the environment-host interface (that is, body surface organs), including the nose, lungs, eyes, skin and digestive tract. It can manifest itself in one organ or in multiple organs within a given time period. Allergic diseases seem to be “self-healing” (no onset for a period of time) or “wandering” (onset of disease in one organ for a period of time, and then in another organ for another period of time). The common manifestations in each system are as follows: 1. Nose: Allergic rhinitis, manifested by recurrent episodes of nasal itching, sneezing (often several in a row), and clear watery nasal discharge; in mild cases, there may be only nasal itching, and children may “make faces” due to mild nasal itching. 2. Lungs: Asthma, manifested as chest tightness, shortness of breath, coughing, wheezing, etc., with intermittent episodes that persist; in atypical cases, it may only manifest as frequent coughing. 3. Eyes: May suffer from allergic conjunctivitis, manifested by itchy eyes, tearing, conjunctival congestion, eyelid swelling, pigmentation around the eyes (dark circles), local discomfort, etc. 4. Skin: n measles, eczema, dermatitis, etc. can be developed. The former manifests itself as sudden white or red wind masses with itchy skin; the latter manifests itself as red rash, oozing with itchy skin, with easy sites on the face and trunk in newborns, and on the elbow and N fossa in preschoolers. 5. Gastrointestinal tract: the manifestations are spasmodic pain in the abdomen, irregular diarrhea, and occasional vomiting.