These two allergic conditions are thought to be the result of immediate allergy and the release of histamine from a number of immune cells. Urticaria (commonly known as “hives”) describes the appearance of a local or generalised blotchy rash, with skin irritation; Angio-oedema (“angio-neurotic oedema”) refers to the acute swelling which affects some people’s eyes, lips and face, causing temporary change in one’s facial features. If the tongue also swells up, the voice and breathing may also be affected. Sometimes the two conditions can coincide. Both are the result of a fast influx of fluid in the skin and other tissues causing acute swelling. Sometimes the symptoms are severe and may lead to shock (anaphylaxis). Occasionally, skin irritation occurs on its own, without any visible skin changes, often triggered by the same causes.

Some unusual types of urticaria are: a) “solar” i.e. caused by the sun b) “cold” i.e. caused by exposure to cold air or ice c) water-induced, e.g. while having a shower d) dermographia i.e. the condition whereby lines or letters can be drawn on someone’s skin e) “auto-immune” or “idiopathic”, suggesting the absence of an obvious cause and f) some blood disorders including Hodgkin’s lymphoma and leukaemia and advanced cancer.

In our experience, types (a)-(e) above obscure some other underlying factors responsible for the continuous activation of the immune system. For example “solar” urticaria, in some cases is the result of using a suntan lotion during sun-bathing, which becomes an irritant in the presence of sun and local heat. Immediate reactions to some foods (e.g. peanuts or seafood) are also uncommon causes but, due to their nature, they have to be investigated thorougly.

Some common causes of urticaria and/or angio-oedema:

• Type B food (delayed, non-atopic) allergy or “intolerance”
• Intolerance to common colorings and other additives, often seen in childhood and some preservatives, which can promote histamine release
• Reactions to common medications, such as penicillin
• Reaction to “salicylates”, aspirin-like substances, naturally found in many foods and of course aspirin and similar medications, known as non-steroidal anti-inflammatories (such as Nurofen, Brufen or Voltarol)
• Reaction to Candida Albicans (a yeast, common cause of thrush) and other fungi such as Thichophytum, in the case of athlete’s foot or fungal nails
• Allergy to some common natural inhalants i.e. pollens, cat or dog dander, horse hair and house dust mites

Most of the above factors tend to “mimic” symptoms of immediate, severe allergy but often involve different mechanisms from those causing an immediate allergy, without its dangers. Contrary to popular belief, intestinal parasites do not cause urticaria or angio-oedema.

Investigations

If immediate/severe allergy is suspected, it is safer to test immunoglobulin-E’s in blood samples. If such allergy is suspected, like with seafood or peanuts, skin prick tests are best avoided, as they carry a risk of potentially severe reactions.

Whilst skin prick tests are widely accepted by the medical profession as accurate and reliable, they are flawed by the fact that they frequently "miss" delayed allergies to foods/”intolerance”, salicylates in various foods and candida (in the absence of accurate laboratory tests, these diagnoses currently remain outside the repertory of day-to-day medicine).

Instead we recommend a number of practical dietary changes and intra-cutaneous tests. Foods, salicylates and some fungi can also be tested this way. Read more....

Treatment

For suspected or proven immediate food allergy, careful avoidance, adrenalin injections (Epipen) or injectable steroids are essential. For patients with chronic or recurrent urticaria the standard treatment is the continuous use of antihistamines, often over a period of some years.
Some inhalant triggers, especially pollens or animal fur are difficult to avoid and often require desensitisation with a low-dose method (Read more on desensitization/immunotherapy….).

If type B food allergies or reactions to salicylates resolve in response to initial dietary changes, one’s diet can slowly be relaxed without the same ill effects (tolerance to these agents improves).

Key points about urticaria/angio-oedema:

a) Life threatening allergies are uncommon but on the increase – it is important they are properly investigated

b) It is possible to identify one or more causes of these symptoms – this process involves skin tests, simple dietary changes or blood tests for immunoglobulin E

c) In most cases, the allergenic agent(s) can be avoided or use preventative measures

d) If the offending items are too many, as occasionally is the case with food intolerance, or too difficult to avoid as with pollen allergy, safe, low-dose methods of desensitization can be used to enhance a better immunity against these items

Audit: over 80% of patients investigated for urticaria and/or angio-oedema between 2001-2005, succeeded in identifying relevant triggers and cleared their symptoms with basic dietary changes or avoidance. The majority did not have immediate/Type A allergy (although they believed they did) and were able to discontinue their antihistamines without recurrence of their symptoms.

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