A raised itchy rash could be urticaria
Urticaria – also known as hives, weals, welts or nettle rash – is a raised, itchy rash that appears on the skin. It may appear on one part of the body or be spread across large areas.
The rash is usually very itchy and ranges in size from a few millimetres to the size of a hand.
Although the affected area may change in appearance within 24 hours, the rash usually settles within a few days.
A much rarer type of urticaria, known as urticaria vasculitis, can cause blood vessels inside the skin to become inflamed. In these cases, the weals last longer than 24 hours, are more painful, and can leave a bruise.
Acute urticaria (also known as short-term urticaria) is a common condition, estimated to affect around one in five 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.
Chronic urticaria (also known as long-term urticaria) is much less common, affecting up to five in every 1,000 people in England.
What causes urticaria?
Urticaria occurs when a trigger causes high levels of histamine and other chemical messengers to be released in the skin.
These substances cause the blood vessels in the affected area of skin to open up (often resulting in redness or pinkness) and become leaky. This extra fluid in the tissues causes swelling and itchiness.
Some cases of long-term urticaria may be caused by the immune system mistakenly attacking healthy tissue. However, this is difficult to diagnose and the treatment options are the same.
Certain triggers may also make the symptoms worse. These include drinking alcohol or caffeine, emotional stress and warm temperature.
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.
If you have persistent urticaria, you may be referred to a skin specialist (dermatologist). Treatment usually involves medication to relieve the symptoms, while identifying and avoiding potential triggers.