physical allergy
Introduction
Introduction to physical allergies Physical allergies are symptoms and signs of allergies caused by physical stimuli such as cold, sunlight, heat or minor trauma. The underlying cause of most cases is unknown. Sometimes drugs or local factors (including certain cosmetics) can induce photosensitivity. In some cases, sensitivity to cold and sunlight can be passively transmitted by serum containing specific IgE antibodies, suggesting the presence of an immune mechanism in which skin proteins altered by physical factors participate as antigens. Recently, IgG and IgM autoantibodies have been found in some cold-induced urticaria patients, suggesting another mechanism. A small number of patients with symptoms caused by cold have cryoglobulin or cold fibrinogen in their serum. These abnormal proteins may be associated with a serious underlying disease (such as malignant lesions, collagen vascular disease, chronic infection). Cold can exacerbate asthma or vasomotor rhinitis, but cold-induced urticaria does not belong to any known allergic tendency. basic knowledge The proportion of illness: 0.006% Susceptible people: no special people Mode of infection: non-infectious Complications: pruritus
Cause
Physical allergic cause
The underlying cause of most cases is unknown. Sometimes drugs or topical factors, including certain cosmetics, can induce photosensitivity. In some cases, sensitivity to cold and sunlight can be passively transmitted by serum containing specific IgE antibodies, suggesting the presence of an immune mechanism in which skin proteins altered by physical factors participate as antigens. Recently, IgG and IgM autoantibodies have been found in some cold-induced urticaria patients, suggesting another mechanism. A small number of patients with symptoms caused by cold have cryoglobulin or cold fibrinogen in their serum. These abnormal proteins may be associated with a serious underlying disease (such as malignant lesions, collagen vascular disease, chronic infection). Cold can exacerbate asthma or vasomotor rhinitis, but cold-induced urticaria does not belong to any known allergic tendency.
According to the survey, about half of the idiopathic cases can be passively transmitted by serum, and heat sensitivity usually causes cholinergic urticaria, which can also be caused by physical exercise, emotional stress or any stimulating sweating in the same patient. Cholinergic urticaria appears to be caused by an abnormally high sensitivity to acetylcholine.
Prevention
Physical allergic prevention
To prevent physical allergies in winter, please reduce the number of baths. If you take a bath every day, it is recommended to use warm water for short-time washing to avoid long-time high water temperature flushing. Usually drink plenty of water, supplement the body and skin water loss, and properly supplement foods containing vitamins A, E, such as carrots, cabbage, peanuts, sesame and so on. In addition, you can also choose glycerin, petroleum jelly, olive oil and other moisturizing skin care products to lock the skin surface moisture, relieve dry itching. Actively exercise. Enhance your physique. Reduce the incidence of this disease.
Complication
Physical allergic complications Complications pruritus
The main complication of this disease is itching.
The cause of scrapie is complicated. Experiments have shown that the dog's skin has a itch-like receptor and is transmitted to the brain through the nerve endings. The release of histamine from the affected area can promote itching. Scratching has an itching effect due to tenderness, but it also promotes the release of more histamine, aggravates itching, and forms an itchy-scratch vicious circle, leading to more serious skin damage and inflammation. Chinese medicine believes that wind evil, wet evil, heat evil, blood deficiency, and worms are the main causes of the disease. The treatment is based on the principle of dispersing wind and dampness, clearing away heat and detoxifying, nourishing blood and moistening dryness, promoting blood circulation and removing blood stasis. Itching effect.
Symptom
Physical allergic symptoms Common symptoms Skin itching Skin at the line of the wind... Edema shock Sun exposure causes skin allergies
The most common complaints are itching and ugly appearance. Cold sensitivity usually causes urticaria and angioedema. The most typical is that after exposure to cold, and when swimming or after swimming, the most serious can occur bronchial asthma or even Histamine-mediated shock, resulting in drowning of the patient, sun exposure can cause urticaria or chronic skin rash, urticaria can also be caused by prolonged vibration stimulation (familial), contact with water (water-borne), and can Rapid or delayed reaction (4-6 hours, occasionally up to 24 hours), protoporphyrin should be considered.
Examine
Physical allergic examination
Skin scratches (a kind of wheal and blush reaction after scratching or hardening the skin) are usually idiopathic, even the first sign of the drug urticaria reaction, the skin of cholinergic urticaria The lesion is small, itchy, scattered small wind group, surrounded by a large erythema area, with 1:5000 acetylcholine for skin test can cause skin lesions in 1/3 of patients, the most reliable test is to wear the patient Exercise on the airtight clothes to stimulate sweating and stimulate symptoms.
Diagnosis
Physical allergic diagnosis
The diagnosis of this disease is clear and does not need to be identified with other diseases.
Allergic dermatitis is a skin disease caused by allergens. It mainly refers to skin diseases such as redness, itching, wheal, peeling, etc. caused by exposure to certain allergens. Specific allergens can be divided into four categories: contact allergens, inhaled allergens, ingested allergens, and injected into allergens. Each type of allergen can cause an allergic reaction, the main manifestations are a variety of dermatitis, eczema, urticaria.
