Urticaria (hives)

Can be a local or generalised blotchy rash accompanied by skin irritation.

What is Urticaria?

Urticaria or hives is a local or generalised blotchy rash which often occurs with skin irritation. Sometimes it can coincide with angio-oedema. These allergic developments are the result of a fast influx of fluid under the skin causing an acute swelling. Sometimes the symptoms are severe and may lead to shock, see section entitled Anaphylaxis. Skin irritation can occur alone without any visible skin changes. Some unusual types of urticaria or hives include: (a) solar, apparently 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 often obscure some other underlying factors which cause the immune system to be in a continuous state of alertness. For example, solar urticaria in some cases is the result of using a suntan lotion during sunbathing which becomes an irritant in the presence of the sun and local heat. Immediate reactions to some foods e.g. peanuts or seafood are also uncommon causes.

Some Common Causes of Urticaria

Type B food, delayed allergy or intolerance
Intolerance to common colourings, preservatives and other additives, often seen in children, which promote histamine release
Reactions to common medications such as penicillin or aspirin
Reaction to chemicals naturally found in some foods
Sensitivity to some fungi
Allergy to common inhalants i.e. pollens, cat or dog dander, horse hair

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

Investigations

If immediate or severe allergy is suspected, it is safer to test immunoglobulin-E's in blood samples. 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 e.g. food intolerance.

Instead, we recommend a number of practical dietary changes and specific blood or intradermal tests. Foods and many other substances can be tested this way.

The diet itself was rigorous but the results were impressive: within two weeks the rash abated and then over the course of the next few weeks the urticaria disappeared completely.

S. L., Surrey

Treatment for Urticaria (hives)

Once the cause of the symptoms has been identified either by blood tests, dietary tests or intradermal tests, the most appropriate course of treatment will be recommended. If avoidance is difficult or impractical then we use a low-dose method of desensitisation to enhance a better tolerance of the offending items. Enzyme Potentiated Desensitisation and Neutralisation are both effective methods of treatment.

Dr Econs treats Urticaria on Channel 4's programme Embarrassing Bodies.

HOW CAN WE HELP YOU?

Identifying the root cause

Life threatening allergies are uncommon but on the increase. It is important they are properly investigated.
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.
In most cases, the allergenic agent(s) can be avoided or preventative measures can be used.
If the causes 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 desensitisation can be used to improve tolerance.

SPECIALIST TIPS AND NOTES

Over 80% of the clients seen in our clinics for urticaria and or angio-oedema between 2001-07 succeeded in identifying relevant triggers and cleared their symptoms with basic dietary changes or avoidance.
The majority did not have a severe allergy and were able to discontinue their antihistamines without recurrence of their symptoms.