What is it?

Urticaria is a condition which causes itchy wheals, or hives, to develop on the skin. For some it also develops alongside angioedema, a swelling within the deeper layers of the skin, including mucous membranes like those in the mouth.

Urticaria triggers

When histamine and other substances are released from allergy cells within the skin, it can cause urticaria. It can come on suddenly (acute urticaria) when you're having an allergic reaction. if the urticaria keeps happening by itself for long periods of time (more than six weeks), it's called chronic urticaria and that is rarely the result of a specific allergy. 

Some people can get an outbreak of angioedema without urticaria. That may be down to a release of histamine but it could also be a condition which has been passed down to you, or because of medications you may be taking.Blood pressure medicines called ACE-inhibitors, such as captopril, lisinopril or ramipril, are especially likely to be the cause.

We can't identify one, single cause for most people with chronic urticaria so the best treatment is to take daily is a non-sedating antihistamine, under the supervision of the doctor. We may also recommend that your GP review your medications, especially if they are for blood pressure.  

Other urticaria triggers

  • heat
  • cold
  • food (mainly for acute urticaria - it is rarely the cause of chronic urticaria)

We see all types of urticaria and angioedema in our clinics. As well as taking a careful history and clinical examination, including a review of all possible triggers, further tests such as skin prick tests or specific immunoglobulin E (IgE) blood tests may be indicated to identify or exclude triggering factors. 

Skin prick testing

Skin prick testing is a universal allergy test and often used to find out what is causing an allergy. 

Oral food challenge

Oral food challenges are tests that use suspected food allergens. The foods that we most commonly test are peanuts, tree nuts and shellfish.

Drug challenge testing

This form of testing comprises of a series of tests to see if you are allergic to certain drugs, all under close medical supervision. 

Molecular diagnosis

Molecular diagnosis covers tests which can assess whether someone has antibodies against a particular protein in a food which causes an allergic reaction.

Nose clinic tests

Patients coming to the nose clinic will have a number of tests, often including an examination using an endoscope, skin prick testing, chest peak expiratory flow and spirometry.

Nasal sprays

Corticosteroid nasal sprays or drops are the most effective standard treatment for hay fever and other nasal allergies.


Antihistamines prevent histamine causing the itching and swelling that occurs when you have allergies.


Allergen immunotherapy is a treatment in which the allergen that triggers an allergic reaction is given in order to suppress unnecessary reactions.

Allergy team contact details


Fulham wing/South block, Fulham Road

Tel:  +44 (0)20 7351 8892
Fax: +44 (0)20 7351 8949