Wind mass

Introduction The wheal is a flat plaque-like skin lesion caused by the limited edema of the dermis, which is pale or reddish, and the size may vary. The number may be more or less, and there may be redness around. Exist for a few hours or more than 10 hours, consciously itching. Leave no trace after disappearing.

Cause

Causes

(1) Drug factors

The drug may cause an allergic reaction or directly stimulate the release of the medium from the mast cell release medium. Such as measles, drug dermatitis.

(2) Food factors

Such as urticaria, measles and other measles, papules and other measles.

(3) Infectious factors

Viruses, bacteria, fungi, and parasites can cause wind wheal. Such as urticaria, sputum rash, schistosomiasis dermatitis, hookworm dermatitis.

(4) Inhalation factors

Wind lumps can be generated by inhaling pollen, animal dander feathers, dust, volatile chemical substances, etc. Such as urticaria.

(5) Insect bites

An allergic reaction or a toxin reaction can cause a wheal. Such as the pimples, the temple measles, insect bite dermatitis, rickets.

(6) Physical factors

Measles such as cold, measles such as sunlight, and skin scratches.

(7) Mental and endocrine factors

Cholinergic measles, menstrual rash.

(8) Genetic factors

Familial cold and other measles, hereditary angioedema, pigmentation and other measles.

(9) The cause is unknown

Pregnancy pruritus, sore dermatitis.

Pathogenesis

The mechanism of the formation of the wind group is relatively complicated, and its mechanism can be divided into two types: allergic reaction and non-allergic reaction.

1. The wheal caused by allergic reaction is mainly type I allergic reaction. Its antibody is IgE and is adsorbed on the surface of mast cells (or basophils). When the antigen is re-entered into the human body by human consumption or inhalation, the antigen-antibody reaction occurs. The mast cell surface receptor is activated, leading to degranulation of mast cells and release of chemical mediators such as histamine, kinin, eosinophil chemotactic factor, and the like. These substances cause microvascular dilatation and hyperemia of the skin, increased permeability of the wall, and wheal of plasma extravasation.

Type II and type III allergies, IgE antibodies are not involved. Antibody IgG, IgM or immune complexes. By activating complement, the release of histamine from mast cells causes wheal with the participation of C3 or C5.

2, non-allergic is a substance such as chemical histamine release agent (morphine, codeine, antibiotics, vitamin Bl, etc. reduce the level of mast cell cyclic adenosine to release the medium such as gelatin. Light, heat, Cold, mechanical stimulation and other factors can also directly cause mastoid degranulation to release histamine. Exercise, drinking, and mental stress can produce cholinergic acetylcholine at the cholinergic nerve endings, causing the increase of mast cell cyclophosphate actamel, promoting mast cells Release of histamine. Choline acetate or due to endocrine factors can directly cause small blood vessels to dilate, and permeability increases to cause wheal.

an examination

Related inspection

Lesion eosinophil count (E) Indirect fluorescent antibody uptake test for leprosy in leprosy (FLA-ABS test) Serum immunoglobulin A (IgA)

(1) medical history

The diagnosis of the wheal is not difficult, but it is difficult to cause the cause of the wheal. It is necessary to ask the medical history and physical examination in detail. Understanding the medical history is not only helpful for diagnosis, but also meaningful for treatment. In the medical history, it is necessary to pay attention to the age, sex, onset time, duration of the wheal, duration of the disease, presence or absence of other rashes, treatment, and history of allergies related to the wheal. Contact history, family history, etc.

(2) Physical examination

The performance of the wind group: check the size and number of the wind group. Color changes, the shape and location of the wheal, and the presence or absence of other skin damage. The wheal of measles such as cholinergic properties is a small wheal of 1 to 3 mm. There is a clear blush around it with a satellite-like small wheal. If the wind group is only found in the exposed area, it may be related to daylight or cold. If the duration of the wheal is too long, more than 24 hours, accompanied by fever, joint pain, decreased blood sedimentation, decreased body disease, pathological examination for leukocyte disruption vasculitis, should be considered as vasculitis and other measles. If the wind group is mainly trunk, it will continue to fade into a brown spot or nodule. After the scratch, red wind can occur on the spot, which can be considered as measles such as pigmentation. Mosquito bites can cause wheal, often local, accompanied by erythema blister and other measles, which are common in children, and more common in spring and autumn. It is characterized by the edema of the bean granules to the peanuts and the large red edematous wheal-like rash. It is not difficult to diagnose the vesicles in the center.

(3) Laboratory inspection

1, the wheal of measles, blood routine can have increased eosinophils. The total number of white blood cells and the increase in neutrophils in acute bacterial infections. The total number of leukocytes caused by drugs can also increase. Some serum complements are reduced.

2, cold measles can measure cold globulin and ice test to help diagnose. It is suspected that inhaling allergens can be done in an intradermal test. Measles such as cholinergicity is positive for exercise and hot water tests. Artificial measles and skin scratch test positive. Light, heat tests and food exclusion tests are helpful for measles such as sunlight and for the diagnosis of food allergens. If the wind group caused by contact with the allergen can be used for skin patch test. Various wheals can be used for histopathological examination as appropriate.

Differential diagnosis

The diagnosis should be differentiated from the following symptoms:

1. Wind-like damage at the skin line: Use a cotton swab (or pencil tip) to scribe on the patient's back skin. Use force to avoid scratching the skin. 1 to 3 minutes after the stroke, the wind-like lesions consistent with the scratches were found at the scribe line, and the diameter was 3 to 5 mm for 10 to 60 minutes. The patient felt itching, which was positive for the skin scratch marks.

2, measles: the rash period showed aggravation of systemic poisoning, body temperature up to 40 ° C, listlessness, lethargy, and sometimes convulsions. Facial edema, skin diagnosis, increased eye secretions, and even adhesions of eyelids are not easy to open, and the flow is thick, the appearance of the above expression is called measles face.

3, skin tingling and itching accompanied by urticaria: when the filamentous sputum invades through the skin around the anus, local skin appears edema, tingling and itching, and often accompanied by linear or banded urticaria, is a roundworm The performance of the diseased perianal skin lesions.

4, urticulite-like skin flushing plaque: gastric carcinoids may secrete histamine, so there may be urticaria-like skin flushing patches.

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