By A.S. (staff writer) , published on November 08, 2022
Hives, also known as urticaria, are a type of skin reaction that creates itching blisters. They can be caused by:
An allergic reaction
A physical trigger, such as cold, water, or pressure
A medical condition, such as an infection or autoimmune disease
Weal is a skin-colored or pale skin swelling that is usually accompanied by erythema and can last anywhere from a few minutes to 24 hours. Just as they vary in color, hives come in many shapes. Some appear as tiny spots or blotches. Others look like thin, raised lines.
Urticaria can coexist with angioedema, more significant swelling of the skin or mucous membranes. Angio-edema describes as a rapid and temporary swelling in the skin or mucus membranes.
Urticaria is classified according to its duration.
Acute Urticaria (< 6 weeks duration, and often gone within hours to days)
Chronic Urticaria (> 6 weeks duration, with daily or episodic weals)
Chronic urticaria may be spontaneous or inducible. Both types may co-exist.
Acute urticaria (also known as short-term urticaria) is a common condition, estimated to affect around 1in 5 people at some point in their lives.
Children are often affected by the condition, as well as women aged 30 to 60, and people with a history of allergies.
Symptoms might continue for minutes, months, or even years.
Hives (also known as urticaria) are distinct from bug bites in various ways:
Hives can appear anywhere on the body and can change shape, move about, disappear, and reemerge in a matter of seconds.
The bumps – red or skin-colored “wheals” with clear edges – usually appear suddenly and go away just as quickly.
When you press the center of a red hive, it turns white, a process is known as "blanching."
Urticaria arises when a trigger induces a release of histamine and other chemical messengers in the skin. These compounds cause the blood vessels in the affected area of the skin to dilate and leak, resulting in redness or pinkness. Swelling and itching are caused by the extra fluid in the tissues.
Histamine is produced for a variety of causes, including:
a food allergy or a reaction to an insect bite or sting
cold or heat exposure
certain medications - such as nonsteroidal anti-inflammatory drugs (NSAIDs) or antibiotics
However, in many cases of urticaria, there is no evident explanation.
Long-term urticaria may be caused by the immune system mistakenly attacking healthy tissue in some situations.
Angioedema – swelling of tissue beneath the surface of the skin – can be mistaken for, or associated with hives. It can be caused by allergic reactions, medications, or a hereditary deficiency of some enzymes. The following symptoms may indicate angioedema:
Swelling in the eyes or mouth
Swelling of the hands, feet or throat
Difficulty breathing, stomach cramps or swelling of the lining of the eyes
Management and Treatment of Hives
The best management of hives is to avoid the triggers. In many cases, treatment isn't needed for urticaria, because the rash often gets better within a few days.
If the itchiness is causing you discomfort, antihistamines can help. Antihistamines are available over the counter at pharmacies – speak to your pharmacist for advice.
A short course of steroid tablets (oral corticosteroids) may occasionally be needed for more severe cases of urticaria.
Severe urticaria episodes may necessitate brief therapy with prednisone, a comparable corticosteroid drug, or an immune modulator, which can alleviate the symptoms.
If your reaction causes swelling of your tongue or lips, or if you have difficulty breathing, your allergist may prescribe an epinephrine (adrenaline) auto-injector for you to carry with you at all times. These could be the first signs of anaphylaxis, a potentially fatal allergic reaction that restricts breathing and sends the body into shock. Epinephrine is the only treatment for anaphylaxis.
Bansal, C. J., et al. (2019). Stress, pseudoallergens, autoimmunity, infection and inflammation in chronic spontaneous urticaria.
Common allergens. (n.d.).
Dabija, D., et al. (2021). Chronic urticaria.