Hives, also known as urticaria, is a common characteristic skin reaction disorder that affects 20% of people at least once in their lifetime and is more common in patients with atopic conditions.
It is a limiting, non-depressed red or white edematous plaque with pruritus.
It is clinically classified according to the course of the disease (duration of 6 weeks): acute urticaria, chronic urticaria.
Clinical classification
1.Unusual urticaria
2.Physical urticaria
Adrenergic urticaria
Cholinergic urticaria
Cold urticaria, limited heat urticaria
Late-onset pressure urticaria
Sunlight urticaria
Shock angioedema
Cutaneous scratching signs: symptomatic cutaneous scratching signs, delayed cutaneous scratching signs
Exercise-induced allergic reactions
3.Contact urticaria
4.Urticaria-like vasculitis and angioedema
Judged by the duration of the cluster.
Urticaria vulgaris 4-36 hours
Physical urticaria 30 minutes-2 hours
Contact urticaria 1-2 hours
Urticaria-like vasculitis 1-7 days
Pathophysiology
Urticaria occurs mainly due to the production of various inflammatory substances (e.g., histamine, 5hydroxytryptamine, etc.) in the body stimulated by various allergic substances acting on H receptors causing a metabolic reaction. Histamine is the most important mediator in the pathogenesis of urticaria and is produced and stored by mast cells. Histamine causes contraction of the endothelial cells of the blood vessels, causing leakage of intravascular fluid from the intercellular space to the extravascular space, causing tissue edema and the formation of wind clumps.
Histamine receptors in the skin are distributed: H1 receptor excitation: axonal reflexes, vasodilation and pruritus; H2 receptor excitation: vasodilation.
Etiological classification of urticaria.
Food: fish, eggs, milk, shrimp ……
Food additives: coloring, sulfites, etc.
Drugs: salicylates, antibiotics, etc.
Infections: bacteria, viruses, fungi, etc.
Inhalants: pollen, fungal spores, dust, etc.
Intrinsic diseases: immune diseases, tumors, etc.
Physical stimuli: cold, heat, light
Hormonal/genetic: pregnancy, progesterone, familial and genetic disorders
Initial evaluation of the patient with urticaria
Skin examination to identify urticaria rather than a bite
Rule out physical urticaria to avoid unnecessary long-term evaluation
Determine acute and chronic urticaria (6-week period)
Understanding the etiology helps guide history taking and physical examination
Evaluation and management of acute urticaria
History taking and physical examination
Laboratory tests
Allergen testing
Treatment of acute urticaria.
1. Avoid exposure to specific allergens
2. Use of H1 receptor antagonists and/or H2 receptor antagonists
3. Management of hypersensitivity reactions: epinephrine, hormones, oxygenation, tracheotomy, cardiopulmonary resuscitation
Exclusionary diagnosis of chronic urticaria
Determine that the lesion is a wind cluster and not an insect bite
Clusters are more generalized, insect bites are more limited
Most lesions >2 cm in diameter and <24 hours in duration
Exclude physical urticaria by skin scratching
History taking for chronic urticaria
Exact time of onset, relationship to drugs, food and drink
Duration: acute (days – weeks), chronic (>6 weeks)
Time of appearance: time of day appearance, time of year appearance, persistent, seasonal
Environment: exposure to pollen, chemicals, home, work
Relationship to physical irritation, joint pain, fever
Preliminary judgment based on duration of individual lesions: lesions lasting <1 hour: physical urticaria, typical wind clumps; <24 hours: typical wind clumps; >25 hours: urticarial vasculitis (scaling and purpura at waning)
Physical examination of chronic urticaria
Size of lesions: papules (cholinergic, stinging), plaques
Thickness of lesions: superficial – most cases; deep – angioedema
Skin scratching: to determine if it is physical in nature
Distribution of lesions: widespread – ingestion, inhalation, visceral disease; limited – physical urticaria, contact urticaria
Look for possible sources of infection: gingivitis, sinusitis, cholecystitis, urinary tract infection
Excluding visceral diseases: thyroid disease, hepatitis, gastritis, tumors, etc.
Laboratory tests for chronic urticaria
Initial screening tests: blood and urine routine, liver function, blood sedimentation
Thyroid function and thyroid antibodies
Excluding infectious diseases: cholecystitis, urinary tract infection, sinusitis
Autoimmune antibody test
Allergen detection: skin test, radioimmunosorbent assay, food test, provocation test
Pathological examination: to determine whether urticaria-like vasculitis is present
Urticaria activity score (UAS)
Urticaria activity score (UAS)
The Urticaria Activity Score (UAS) includes a calculation of the number of clusters and the degree of itching.
The score is 1-3 depending on the number of clusters.
0 C less than 10 small clusters (< 3 cm in diameter);
1 C 10 – 50 small clusters or less than 10 large clusters (> 3 cm in diameter);
2 C More than 50 small clusters or 10- 50 large clusters;
3 C Almost all the torso was involved.
Pruritus severity score 0-3.
0, none;
1, Mild;
2, moderate;
3, Severe
Angioedema.
Angioedema (angioneurotic edema): is an urticaria-like swelling due to increased vascular permeability in the subcutaneous tissue of the skin and mucous membranes and in the submucosa of the respiratory and digestive tracts.
Urticaria and angioedema often coexist and have a common etiology
Types of angioedema.
Acquired angioedema
Acute angioedema: allergic IgE-mediated, contrast agents, serum sickness, cold urticaria
Chronic recurrent angioedema: idiopathic, acquired C1 inhibitor deficiency
Angioedema – eosinophilic syndrome
Hereditary angioedema.
Differential diagnosis of angioedema.
1, herpetiform aspergillosis or herpes-like dermatitis
2, drug rash
3, erythema multiforme/rubella marginatum
4, papular urticaria (insect bite dermatitis)
5, Pruritic urticaria papules and plaques of pregnancy
6.Pigmentary urticaria
7.Still disease
8.Urticaria-like vasculitis
Treatment of angioedema
Antihistamines: H1 receptor antagonists, H2 receptor antagonists
Tricyclic antihistamines
Mast cell membrane stabilizers: ketotifen, trinostat
Leukotriene receptor antagonists: adrenaline
Glucocorticoids
Immunotherapy: cyclosporine, Xiaoser
H1 receptor antagonists commonly used in clinical anti-allergy treatment.
Ethanolamines: Benadryl, Clomastine, etc.
Hydroxylamines: paracetamol, ketamine, etc.
Piperazines: cyproheptadine, loratadine, imipramine, desloratadine, etc.
Piperazines: Dechloroxazine, Cetirizine, Levocetirizine, etc.
Phenothiazines: promethazine
Anti-allergic drug treatment for special groups (under the guidance of clinicians)
1.Medication for maternal and lactating patients: Unless the condition is severe or stubborn, the use of conventional anti-allergy drugs is not advocated, calcium can be used, and a few patients can refer to the drugs approved by the FDA for Class B or above.
2.Medication for infants and other pediatric patients (omitted)
3, the medication of school students (omitted)
4.Medication for patients with certain special jobs and types of work (omitted)
5.Patients with liver and kidney dysfunction or other special diseases (omitted)
Recommendation: 1. It is recommended that all patients with urticaria should go to a regular hospital and ask a dermatologist for diagnosis and treatment.
2. Routine blood and urine tests should be performed in women and children with urticaria to exclude infection factors (anti-infection treatment is the key to rapid control of acute urticaria combined with infection)!
3, more complex or chronic, refractory urticaria patients, it is recommended to use 2-3 different categories of anti-allergy drugs in combination therapy, taking a long time, after a month of complete control of the disease, and then consider the gradual reduction of drugs. And the process of drug reduction treatment should also be long: half a month for a drug reduction treatment adjustment period, each half month to reduce a drug, during this period to closely observe whether there is a relapse of the disease during the drug reduction period, if there is a relapse need to resume the initial treatment program or replace the new program; some serious patients may have to consider the use of tretinoin and other drugs with bone marrow suppression, liver damage to control the disease.
4.Sometimes the clinical itching and wind masses are relieved, but the scratch sign (+) indicates that the disease is still not completely controlled, so it is necessary to go to the hospital to ask the clinician to adjust the drug treatment plan in time.
5. For patients with abnormal liver or kidney function or other special diseases, please select drugs via different metabolic routes for safe use under the guidance of clinicians or pharmacists!