Hives, also known as urticaria, appear after the body releases histamine. This triggers an allergic reaction, resulting in red, raised itchy small bumps on the skin.

Acute urticaria lasts only for a few days, and is usually caused by an infection (especially viral infections of the upper respiratory tract), drugs, (such as penicillin) and foods (especially shellfish, fish, eggs or nuts).

Chronic urticaria lasts for more than six weeks and may be due to other causes -- autoimmune disease, stress, connective tissue disease or physical stimuli (pressure, heat, cold, sun, water, exercise).

A commonly used blood test to detect allergies is the RAST test (or immunoglobulin IgE test). However, this test is less accurate in detecting allergens than a skin test. A skin-prick test will detect causes of immediate allergic reactions, while a skin-patch test detects allergens that can cause a delayed allergic reaction (those that develop over the course of a few days).

Other tests that may help identify the allergen include stool examination for ova and parasites, antinuclear antibody titre, thyroid function/antibody levels, as well as a full blood count and differential white cell count. A detailed record of your activities, exposures and diet is vital. In many cases of urticaria, the trigger is never identified.

Even if it is known, some patients may be unable to avoid exposure or reaction. This can be frustrating for both the patient and healthcare practitioner, but there are many options for treatment management. General measures include staying in a cool, calm environment. Wear loose, comfortable clothes. Take lukewarm-to-cool baths with added baking soda or colloidal oatmeal (Aveeno).

Antihistamines are the mainstay of treatment for urticaria. It is best to take them on a regular basis rather than as needed, in order to reduce inflammation and prevent symptom development.

Other prescribed medication that can help includes the leukotriene receptor antagonists such as Singulair, taken regularly.

Corticosteroids are another option, generally used for severe cases. Alternatively, Quercetin is a bioflavonoid that has anti-inflammatory properties. It is found in many foods, including green tea, apples, berries and brassica vegetables. It is also available in supplement form. Butterbur is a herbal treatment used to treat allergic rhinitis; it lowers histamine levels and may be an alternative to consider instead of antihistamines.

The standard dose is 50-100mg of standardised extract twice a day with meals. It should not be taken in patients with liver disease, and liver function blood tests should be done in those who take it for longer than 3-4 weeks.

Homeopathic treatment may help but as each patient is assessed individually, there is no one remedy that suits all. Only consult trained and accredited practitioners.

- Dr Niamh Houston