Chronic urticaria and angioedema

Marcus Maurer, Professor of Dermatological Allergology and Director of Research, Charité University Hospital, Berlin
A presentation at the Allergy Research Foundation conference: The difficult to manage allergy patient. November 2012

Urticaria is one of the most difficult conditions in allergy to manage. It can dramatically affect the patient's quality of life yet most patients think that there is no treatment. Nearly all urticaria will resolve naturally, eventually, but this can take up to seven years and the need is to keep the patient symptom free during that period.

Symptoms and diagnosis

The symptoms of urticaria are 'wheal and flare' (raised, extremely itchy bumps) plus angioedema (swelling), normally together although they can appear separately. Both symptoms can also be symptoms of other conditions although these are very rare.

The condition nearly always appears in later life, not in childhood.

Urticaria is hard to treat as the cause is rarely unknown – although it is never caused by an allergy so skin prick testing is not helpful. However, induced (as opposed to spontaneous) urticaria can be triggered (but not caused) by:
• cold
• sun
• heat
• delayed pressure
• contact with specific substances
• water

Spontaneous urticaria appears to be caused by:

• auto reactivity – approximately 20% of cases – when something in the body reacts to something else in the body, often to something circulating in the blood;

• bacterial infection – approximately 25% of cases. Around 50% of us carry bacterial infections but they do not trigger urticaria. If infections are eliminated, around 50% of spontaneous urticaria sufferers will benefit;

• intolerance – approximately 29% of cases. This intolerance is never to food but may be to additives or preservatives. There are no tests so elimination of the most likely substances (all drugs that can induce urticaria, pseudo allergens and histamine) for at least 14 days followed by a challenge is the only way to identify an intolerance. Again, around 50% of spontaneous urticaria sufferers will benefit.

Therapeutic strategies

• Find and eliminate the cause/triggers if possible.

• If this is not possible, treat with non-sedating anti-histamines.
Antihistamines are nearly always under dosed in urticaria. If they do not work at the original dose, that that dose should be upped four times. However, it is important to up dose with the same antihistamine, not to give four doses of different antihistamines as each one works in a slightly different way and the effect will be dissipated.

• Anti IgE drugs.
Although urticaria is never cause by an allergy, anti-IgE drugs appear to work with some urticaria patients for whom antihistamines do not work – even though they do not have raised IgE. However they only work as long as the patient continue to take the drug.

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