Urticaria, often referred to as “rubella”, is a common allergy-induced skin disease, with skin manifestations in mild cases, and shock and respiratory distress in severe cases, which can be life-threatening if not treated promptly. The following is a detailed discussion of the causes, clinical manifestations, prevention and treatment of urticaria, with case studies.
I. Causes
For acute urticaria, there are mostly triggering factors, while for chronic urticaria, most patients cannot find the exact cause.
Food is the most common cause, including animal proteins such as fish, shrimp and crab, beef and lamb, milk and eggs, and plant-based ones such as strawberries, onions, ginger and garlic, and tomatoes; some food additives can also cause urticaria. Secondly, drugs can also cause urticaria, the most common drugs such as penicillin, cephalosporin antibiotics, serum preparations such as tetanus and antipyretic analgesics. Infectious factors also tend to cause this disease such as viral, bacterial, fungal and parasitic infections. Various physical factors such as sunlight, cold, heat, friction and pressure. Various inhalants such as animal fur, pollen, etc. are also likely to cause urticaria. Systemic diseases such as autoimmune diseases such as lupus erythematosus, malignant tumors, and metabolic disorders are also causes of chronic urticaria. Other diseases such as mental stress, endocrine abnormalities, etc.
Clinical manifestations
The disease can occur at any age, according to the course of the disease can be divided into acute and chronic urticaria, regardless of the acute and chronic, the appearance of wind masses on the skin is its basic damage.
For acute urticaria, the onset of the disease is more acute, and the patient feels itchy skin at the beginning, and soon there are wind clusters (commonly known as rubella bumps) on the itchy area. The rash usually lasts no more than 24 hours, and untreated urticaria usually has an orange peel-like appearance and can be red or pale white in color. Some patients may have nausea, vomiting, headache, head swelling, abdominal pain, diarrhea, and in severe cases, systemic symptoms such as chest tightness, discomfort, pallor, accelerated heart rate, weak pulse, decreased blood pressure, and shortness of breath. Acute urticaria is often cured within a short period of time after timely treatment, so it is called acute urticaria.
If there are repeated attacks of urticaria for more than 6 weeks, it is called chronic urticaria, which is sometimes more or less frequent and recurrent for months or years, but there are occasional acute attacks.
In addition to acute and chronic urticaria, there are also the following special types of urticaria, mainly including the following:
1. Skin scratching sign/artificial urticaria
This is a weak mechanical stimulus such as scratching or rubbing of clothing that can produce a wind cluster on the skin, often in the direction of scratching, accompanied by itching.
2.Pressure urticaria
It may be accompanied by fever, headache, arthralgia, general discomfort and mildly increased white blood cell count. Localized widespread swelling resembles angioedema and is likely to occur in the hands, feet and buttocks.
3.Cholinergic urticaria
The patient feels tingling and itching of the skin all over the body. Mostly occurs during or after exercise, heat, emotional stress, eating irritating food, accompanied by itching, stinging, burning.
4.Cold urticaria
Can be divided into familial and acquired two, the former is more rare. Acquired is more common, patients often occur when the temperature drops or after contact with cold water, within a few minutes of local itchy edema and wind masses, mostly on the face, hands, serious other parts can also be involved. Headache, skin flushing, hypotension, and even shock can occur.
5.Solar urticaria
After the skin is exposed to sunlight for a few minutes, local itching, erythema, and wind masses appear rapidly. The rash may be accompanied by chills, fatigue, fainting, and intestinal cramps.
6.Contact urticaria
It is characterized by skin contact with certain allergens after the occurrence of wind and erythema.
7, Others include heat urticaria, motor urticaria, tremor urticaria, water urticaria, adrenergic urticaria, current urticaria and other more rare types of urticaria.
III. Diagnosis
It is easy to diagnose urticaria, and the diagnosis can be confirmed based on the clinical appearance of wind clusters with itching, but it is often difficult to determine the cause of urticaria, especially chronic urticaria should be as clear as possible the cause of urticaria, which is also the key to treating recurrent chronic urticaria.
IV. Treatment
1.General treatment
Each patient should try to find the cause of the attack and avoid it. For the infection caused, the primary infection should be actively treated. If the allergy is caused by drugs, stop using them. If you are allergic to food, do not eat the food again. If the cause is not clear, you can do allergen test.
2.Medication
(1) Antihistamines
Mainly H receptor antagonists, with strong antihistamine and anti-inflammatory mediators, is the first-line drugs for the treatment of various types of urticaria. H1 receptor antagonists commonly used are the first generation (cycloheximide, paracetamol), the second generation (cetirizine, imipramine, loratadine, epalrestine), etc. H1 receptor antagonists, especially the first generation have more drowsiness, resulting in poor urination and other adverse effects, the application should take into account the patient’s occupation, such as high-altitude work, drivers, etc. and whether the elderly patients have prostate hypertrophy; when individual treatment is ineffective, the The H1 receptor antagonist can be used in combination with two different types of H1 receptor antagonists. Commonly used H2 receptor antagonists are cimetidine, ranitidine, famotidine, etc., rarely used alone to treat urticaria, often combined with H1 receptor antagonists to play a better therapeutic role.
(2) Doxepin
It belongs to the tricyclic antidepressants. For patients with urticaria in which antihistamines are ineffective, doxepin is a better choice of drugs, especially for chronic urticaria, and the adverse effects are small.
(3) Drugs that inhibit the degranulation of mast cells and reduce the release of histamine, commonly used include ketotilol, sodium cromoglycate, trenbolone, montelukast, etc.
(4) Glucocorticoids
Only as second-line drugs for the treatment of urticaria, they are generally used for severe acute urticaria with systemic symptoms such as gastrointestinal symptoms, hypotension, dyspnea and chest tightness. The aim is to provide early relief of symptoms and avoid further progression of the disease. Commonly used drugs include prednisone or prednisolone, dexamethasone, betamethasone, etc.
(5) Immunosuppressants
Immunosuppressants can be used only when satisfactory results cannot be achieved with the above treatments, including: cyclosporine, rhodopsin, azathioprine, cyclophosphamide, methotrexate and immunoglobulin. Due to the adverse effects of immunosuppressants, they are generally not recommended for the treatment of urticaria.
(6) Other drugs such as drugs that reduce vascular permeability such as vitamin C, vitamin P, calcium, etc., are often combined with antihistamines.