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Respiratory allergy, urticaria and anaphylaxis

Credit: NHS Photo Library
People with hay fever (rhinitis) have inflamed lining in their nose, which causes it to be blocked, running and itchy, as well as causing sneezing. Many cases of rhinitis are due to allergy; for example, summer hay fever is caused by grass pollen allergy. However, not all rhinitis is caused by allergies. There are a number of different causes of non-allergic rhinitis, including structural problems in the nose, such as a deviated nasal septum, perforated septum or adenoidal hypertrophy, or inflammatory problems, such as nasal polyps. Medication taken for other conditions can also cause rhinitis. 

Rhinosinusitis is a more complex condition. It involves inflammation of the sinuses in addition to the lining of the nose. Symptoms typically include nasal blockage and congestion, facial pain and discomfort, and nasal discharge, either from the front of the nose or as a post-nasal drip. Many of the causes are the same as for non-allergic rhinitis. 

Patients who are referred with rhinitis or rhinosinusitis are seen in our joint medical-surgical nose clinic. This clinic has both allergy doctors and ENT (ear, nose and throat) surgeons from Charing Cross Hospital. They will take a full history of the problem and may also undertake other tests, such as allergy skin prick testslung function testing and examination of the nose using an endoscope. Other tests may be necessary, including blood tests and CT (computed tomography) scans of the sinuses. Following a diagnosis, if surgery is needed, this will also be arranged in the clinic, but will take place at Charing Cross Hospital in Hammersmith. 
Urticaria is a condition which involves the development of itchy wheals (hives) on the skin. Some people also have angioedema, which is a swelling of the deeper layers of the skin, including mucous membranes such as those within the mouth. Urticaria is caused by histamine and other substances released from allergy cells within the skin called mast cells. A sudden onset of urticaria (acute urticaria) can happen when someone is having an allergic reaction. However, if the urticaria keeps happening spontaneously but continues for a period of more than six weeks, it is called chronic urticaria. Chronic urticaria is rarely the result of a specific allergy.

Angioedema appearing on its own without the itchy urticarial wheals is not necessarily caused by mast cells releasing histamine. Another substance called bradykinin may be responsible. This type of isolated angioedema may be hereditary or happen because people are taking certain medications. Blood pressure medicines called ACE-inhibitors, such as captopril, lisinopril or ramipril, are especially likely to be the cause.

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. Some external factors, such as heat, cold, pressure and medications, can all be involved. Food may also be a trigger for acute urticaria, but is rarely involved in chronic urticaria. 

It is not possible to identify one single cause for most people with chronic urticaria. The best treatment  is to take non-sedating antihistamines daily, under the supervision of the doctor. The doctor might also recommend that the patient's GP carries out a review of medications, especially if the patient is on blood pressure medicine. 
Selection of nuts - molecular diagnosis
Anaphylaxis is a serious allergic reaction that can be life threatening or fatal. The reaction happens quickly and usually involves difficulty in breathing, feeling faint or lightheaded and can lead to a collapse. People might get skin wheals and/or angioedema before they start having difficulties in breathing. 

Key triggers include food, drugs and stinging insects such as bees, wasps and hornets. Sometimes it is difficult or impossible to find a clear trigger; sometimes it is caused by a combination of occurrences. For example, people may only have anaphylaxis when exercising and sometimes a combination of exercise and certain foods or medications can cause the problem. 

Anyone who has had an anaphylactic reaction should have specialist follow-up in order to identify and avoid the trigger(s). Sometimes their history and skin or blood tests can be enough to identify the trigger, but diagnosis may also involve careful challenge (provocation) testing in hospital, under medical supervision. Patients who have had an anaphylactic reaction should receive written information listing the triggers involved and giving a plan of how to manage any future episodes. Self-injected adrenaline is the best treatment to give immediately. Other drugs such as corticosteroids and antihistamines may be given in addition. In the case of anaphylactic reactions to insect stings, specific allergen immunotherapy (‘desensitisation’) may be necessary to protect against further allergic reactions. 

The Anaphylaxis Campaign website offers further support for those living with anaphylaxis and their families.

Royal Brompton

Sydney Street,
London SW3 6NP
Tel: +44 (0)20 7352 8121


  • Read about the allergy clinics held by the Trust
  • Find out more information about treatment, such as nasal sprays and antihistamines, for these conditions