周皮肤荨麻疹Urticaria

1、Urticaria,CHEN Aijun MD Department of Dematology, The First Affiliated Hospital, Chongqing Medical University,Definition,Urticaria is a very common disease and is a vascular reaction of the skin characterized by the appearance of wheals, white or red evanescent plaques generally surrounded by a red

2、halo or flare and associated with severe itching, stinging, or pricking sensations.,These are wheals, white or red evanescent plaques generally surrounded by a red halo or flare. Fast appearing and diminishing, no trace after diminishing.,Etiology,Foods Medicines Infections Physical factors Animals

3、and plants Spirit factors Diseases of internal organs,Etiology,1. Foods The most allergenic foods are shellfish, shrimps, crab, chocolate, nuts, peanuts, tomatoes, strawberries, melons, pork, cheese, garlic, onions, and spices. Eggs and milk always induce urticaria in children.,2. Medicines Many med

4、icines can start urticaria by allergy, the most common drugs are as follows: penicillin, serum, vaccine, furazolidone, sulfanilamide and so on . Sometimes a few drugs can directly stimulate mast cells to produce histamine, like aspirin, morphine, codeine, quinine, etc.,3. Infections Infections cause

5、d by all organisms are another possible reasons to induce urticaria. The most common organism is virus of upper respiratory and staphylococcus aureus. Chronic infections of the patients cannot be easy verified as the pathogen of urticaria; it must be tested by therapy.,4. Physical factors: Cold, hot

6、, sunlight, friction and pressure 5. Animals and plants : Urticaria can be induced by animals fur skin or pollen or stinging of insects. 6. Spirit factors: In some cases, stress can trigger urticaria, but in another cases stress may lead to histamine releasing.,7. Diseases of internal organs,Rheumat

7、ic disorder, rheumatoid arthritis, systemic lupus erythema, malignant tumor, disorder of endocrine and some others can be another reasons of urticaria.,Pathogenesis,1. Allergy,anaphylactic type immune complex type and allergic vasculitis The wheal results from increased capillary permeability, which

8、 allows proteins and fluids to extravasate. Capillary permeability results from the increased release of histamine from the mast cells situated around the capillaries.,Allergy,The mast cell is the primary effector cell in urticarial reactions. The mast cell granules containing heparin and histamine

9、disappear or almost disappear during wheal, and then degranulated.,2. Not coming from allergy,Some factors can lead to releasing of histamine from mast cells. They include medicines like atropine, morphine, quinine, aspirin, pilocarpine, papaverine, polymyxin B, codeine, and etc. or some simple comp

10、ound like amine, tween 80. Another factors are toxins coming from snake, bacteria, jellyfish, insect and so on. Food like animal with shells, lobster, mushroom and strawberry can stimulate histamine release in some cases.,Clinical manifestations,Acute urticaria Chronic urticaria Special sorts of urt

11、icaria,1.Acute urticaria,Acute urticaria always occurs abruptly, it will evolve over days to weeks, producing evanescent wheals that individually rarely last more than 12 hours, with complete resolution of the urticaria within 6 weeks of onset.,There are many wheals on the patients trunk.,Sometimes

12、it will show allergic shock features, blood pressure of patients may fall, or they will have abdomen ache, or are panicky, dysphoria, nausea and vomitus. Some patients will have severe abdomen ache, like acute abdomen. Dyspnea will appear on some cases if edema appear at respiratory tract. In few ca

13、ses it may accompanied by septicemia while the patients have high fever, shivering with cold or fear.,2. Chronic urticaria,Daily episodes of urticaria and/or angioedema lasting more than 6 weeks is designated chronic urticaria. which predominantly affects adults and is twice as common in women as in

14、 men.,General symptoms of chronic urticaria are mild, more wheals or a few wheals, it will recur repeatedly, keeping for several months or years, it will sharpen in special time or not. Causes cannot be found in many cases.,3. Dermatographism,Dermatographism is also known as factitious urticaria and

15、 is a sharply localized edema or wheal with a surrounding erythematous flare occurring within seconds to minutes after the skin has been scratched.,Dermatographism is a sharply localized edema or wheal with a surrounding erythematous flare occurring within seconds to minutes after the skin has been

16、scratched.,4. Cholinergic urticaria,Cholinergic urticaria is produced by the action of acetylcholine on the mast cell, characterized by minute, highly pruritic, punctate wheals or papules. Lesions persist 30 to 90 minutes and are followed by a refractory period up to 24 hours.,5. Solar urticaria,It

17、is always induced by media or longultraviolet ray, and appears soon on unshielded skin when exposed to sunlight. It is classified by the wavelengths of light that precipitate in the reaction.,6. Pressure urticaria,It is characterized by the development of swelling with pain that occurs 4 to 6 hours

18、after local area being pressed. There may be a latent period of as much as 24 hours before lesions develop.,7. Angioedema,It always occur at rarefaction areas, like eyelid, lip, external genital organs, hand and foot. It appears abruptly, and shows localized edema features, it will diminish after 1

19、to 3 days. If angioedema appears at mucosa of larynx, it can cause dyspnea, even death.,The patients lip shows localized edema features, and it will diminish after 1 to 3 days.,8.Cold urticaria: Put a piece of ice on the patients arm for a few minutes.,A few minutes later we can see wheals on the si

20、te.,Diagnosis,The diagnosis of urticaria can be made upon its typical clinical manitestations, in details: wheals; fast appearing and diminishing; no trace after diminishing and specialties at every phase. It can be diagnosed easily, but cause-diagnosis are very difficult in many cases.,Systemic tre

21、atment,1. Acute urticaria,The mainstay of treatment of acute urticaria is administration of antihistamines. Vitamine C can also be used to decrease permeabilities of vessels. 654-2 or other same sorts of drugs can be chosen in acute urticaria followed by abdomen-ache. If it were accompanied by infec

22、tion of bacteria, appropriate antibiotics therapy would be necessary.,shock or laryngeal edema or dyspnea,Immediate injection with 0.1% adrenalin at 0.5ml by subcutaneous part. Inspiring with oxygen. Intravenous injection with hydrocortisone at 0.2 to 0.3g in 500ml glucose. After about 15 minutes, 0.1% adrenalin at 0.5ml can be used again. 0.2g aminophylline is used for cases with bronchospasm.,2. Chronic urticaria,Looking for the real reason is very important, and corticoid must be avoided. Administration of antihistamines again and should be taken o