Urticaria is characterised by very itchy weals (hives), with or without surrounding erythematous flares. The name urticaria is derived from the common European stinging nettle Urtica dioica. Urticaria can be acute or chronic, spontaneous or inducible. A weal (or wheal) is a superficial skin-coloured or pale skin swelling, usually surrounded by erythema that lasts anything from a few minutes to 24 hours.
Call +91 8850611780 to book your consultation with Dr Vivek Mishra.
Urticaria is classified according to its duration.
Chronic urticaria may be spontaneous or inducible. Both types may co-exist.
One in five children or adults has an episode of acute urticaria during their lifetime. It affects all races and both sexes.
Acute urticaria can occur in newborns and infants but is uncommon. Acute urticaria in children is usually caused by infection, even if afebrile. In older children food, medication, and inhaled allergens are also important causes. In adults urticaria is usually idiopathic and spontaneous.
Acute urticaria with fever can be the first sign of COVID-19 infection.
Chronic spontaneous urticaria affects 0.5–2% of the population; in some series, two-thirds are women. Chronic inducible urticaria is however more common. There are genetic and autoimmune associations.
Urticarial weals can be a few millimetres or several centimetres in diameter, coloured white or red, with or without a red flare. Each weal may last a few minutes or several hours and may change shape. Weals may be round, or form rings, a map-like pattern, or giant patches.
Urticaria can affect any site of the body and tends to be distributed widely.
Angioedema is more often localised. It commonly affects the face (especially eyelids and perioral sites), hands, feet, and genitalia. It may involve tongue, uvula, soft palate, or larynx.
Serum sickness due to blood transfusion and serum sickness-like reactions due to certain drugs cause acute urticaria leaving bruises, fever, swollen lymph glands, joint pain and swelling.
In chronic inducible urticaria, weals appear about 5 minutes after the stimulus and last a few minutes or up to one hour. Characteristically, weals are:
The weals are more persistent in chronic spontaneous urticaria, but each individual lesion will resolve within 24 hours. They may occur at certain times of the day.
A skin allergy is when skin becomes irritated because the immune system reacted to something that is usually harmless. This is called an allergic reaction. An allergic reaction can cause rash, itching, burning, redness, bumps, hives, and swelling. Many different allergens can cause a reaction. Below are some of the most common allergic skin conditions:
Atopic dermatitis (dur-muh-tahy-tis), or eczema, is when the skin becomes easily irritated, itchy, and dry. It is the most common allergic skin condition, and is more common in children than adults. Eczema is linked to both genetic (inherited from parents) and environmental factors. It is connected to asthma, food allergies, and seasonal allergies. Some things can make eczema flare up, such as certain foods, stress, soaps and lotions, or cold and dry air.
Allergic contact dermatitis is when something touches the skin and causes a reaction. For example, some people are allergic to the metal nickel and will have a skin reaction if jewelry made with nickel touches their skin. A reaction to poison ivy is another example. Many people have an allergic reaction to the oil on a poison ivy or poison oak plant.
Urticaria (ur-ti-kair-ee-uh), or hives, are raised bumps on the skin that form because of an allergic reaction. These bumps are also called welts or wheals. A person may get hives after eating a food they’re allergic to. The bumps are a result of histamine that the body releases in response to the allergen. Things besides allergies can cause hives as well, such as a bug bite.
Angioedema (an-jee-oh-i-dee-muh) is swelling deep in the skin. It often happens on places like the eyelids, lips, and throat, and often happens together with hives.
The symptoms of a skin allergy vary depending on the type of reaction:
Eczema causes an itchy, scaly, red, dry rash, especially on the face, hands, elbows, and knees. Sometimes eczema weeps clear fluid as well.
Allergic contact dermatitis causes a rash that may be itchy but is often painful. The rash may have both raised bumps and blisters. The reaction may happen right away or it may be up to 48 hours after your skin was exposed to whatever is causing it to react.
Hives are raised, flat, itchy bumps that may also be tender. Hives are a sign of a potentially serious allergic reaction.
Angioedema is a type of swelling. For example, angioedema on the eyelid can cause your eye to be swollen shut. When it happens in the throat, it is an emergency because the swelling makes it hard to breathe.
A skin allergy is a skin condition where the immune systems reacts strongly to an allergen. The reaction can cause irritation, rashes, swelling, or hives. The cause of the allergy depends on the condition and the allergen.
To diagnose a skin allergy condition, your doctor may:
Ask questions about your skin, symptoms you are having, and when it happens.
Examine your skin. The doctor may also look at your eyes, nose, throat, and chest to check for signs of an allergy.
Recommend allergy testing:
Patch test. This test checks for allergic contact dermatitis. The doctor puts a small amount of allergen on your skin, covers it with a bandage, and lets it sit for 2 to 4 days. The doctor checks for signs of a reaction — usually a rash right under the bandage.
Treatment for skin allergy varies depending on the problem and the allergen, but usually includes two approaches:
Below are some recommendations for treating each of the allergic skin reaction types.