Urticaria (hives) is a very common allergic skin disorder, especially among children and young people. It is characterized by red skin patches, skin level or raised, varying in shape and size, and accompanied by itching. The patches can also erupt in the form of white blisters, surrounded by red flares, and the main feature is that the skin changes last up to several hours, whereas new ones appear in bouts. If the allergic reaction involves the junction between the skin and the mucous membrane (places such as the eyelids, lips, tongue or throat). Swelling (angioedema) may occur, it is accompanied by pain and sometimes by itching, and it can cause respiratory problems.
What causes urticaria?
Urticaria occurs when an allergen permeates the body, which leads to an allergic reaction in the blood vessels, and results in the typical skin change – urticaria (hives). It is most frequently caused by medication, certain foodstuffs, bacterial infections, pollen, parasites, or insect poison.
Small children most often have urticaria which is caused by foodstuffs, food allergens such as hazelnuts, almonds, walnuts, peanuts, chocolate, honey, berries and egg yolk. If the urticaria was caused by medication or an antibiotic, it is advised that the allergen is avoided in the future. As regards foodstuffs, after the skin changes have disappeared, different foodstuffs can be reintroduced into the child’s diet, one at a time, with 7 day pauses in between. If a certain product continues to cause swelling and breathing problems, it is certainly advised against its further use. Also, urticaria in children is very often caused by intestinal parasites.
There are numerous causes of urticaria, in addition to the above stated, and in 70% of the cases the cause is unknown. Aspirin, non-steroidal anti-inflammatory drugs, azo dyes and benzoates can cause false or pseudo-allergies, so they should be strictly avoided.
How long does urticaria last?
Urticaria usually lasts several days or weeks. If it is present for more than 6 weeks, it requires more detailed examination, and in such cases it is called chronic urticaria. Chronic urticaria can be a symptom of systemic auto-immune diseases or vasculitis.
How is the testing done and what kind of treatment is needed?
If the cause (trigger) of urticaria is clearly recognized, it needs to be avoided, in addition to the use of antihistamines. Detailed blood tests and bacteriological testing can be carried out only after 6 weeks, whereas remission of acute urticaria is expected during this time. If a particular allergen is suspected, testing for IgE antibodies is carried out. In persons experiencing digestive symptoms in addition to the urticaria, testing for Helicobacter pylori is advised. Treatment involves antihistamines, sedating and non-sedating, and they are not to be taken while allergy testing is being carried out. In persons with angioedema, urgent corticosteroid treatment is indicated.
What are the specific types of urticaria?
Dermographism is the most common type of physical urticaria, where skin changes (urticae) appear under moderate skin pressure, such as pressing on the skin or by scratching. Redness, swelling and itching can last from 15 to 30 minutes. This form of urticaria is present in persons with an atopic constitution, and it does not require treatment.
This type of urticaria occurs when skin and mucosa are in contact with contact with cold drinks, cold air or cold wind. Redness, swelling and itching appears on the exposed body parts. It is advised that patients prone to this type of urticaria avoid sudden contact with cold water (including jumping into cold water) due to the risk of generalized urticaria.
Solar urticaria appears several minutes following sun exposure and subsides within one hour. Body parts which are constantly exposed to sunlight, such as the face and hands, are not susceptible, which is not the case with polymorphic urticaria.
Cholinergic urticaria appears in young people after strenuous physical exertion and a rise in body temperature, after eating very spicy food or following emotional stress. Small, pale papules surrounded by red flares appear on the hands, abdomen or chest. They are accompanied by itching. They subside on their own within 30 minutes. Susceptible persons are advised to avoid excessive heating of the body, tension and strenuous physical activity.
Contact urticaria appears several minutes after skin contact with allergens, most often foodstuffs, plants, medication or additives found in food or cosmetics. It is common in certain professions, such as bakers, hair dressers, homemakers and chefs.
Urticaria pigmentosa breaks out as part of the mastocitosis disease, which is characterized by an eruption of urticae after scratching dark red and tan skin spots.