Hives

• Hives are localized, itchy pink swellings (wheals) that occur on any part of the skin, lasting a few minutes to a few hours, before fading away, within 48 hours, leaving no trace.
• Hives are very common, affecting 15% to 20% of the population.
• In most people, hives go away within a few days to a few weeks.
• Occasionally, a person may continue to have hives for many years.
• When urticaria occurs around loose tissues of the eyes or lips, the tissue may swell excessively. Although frightening in appearance, the swelling called angioedema goes away in less than 24 hours.

• A hive is produced by fluid leaking through small blood vessel in the skin.
• Such changes are brought about by the release of a natural chemical called histamine from mast cells which lie along the blood vessels in the skin.

• Common causes of urticaria are infections, foods, drugs and physical agents (e.g. heat, sweating, exercise, sunlight, pressure, cold).
• Occasionally, insect bites and internal disease may also be responsible.
• Sometimes, no cause can be found.
• Common foods that cause urticaria include nuts, eggs, fresh citrus fruits, tomatoes and shellfish. Food additives and preservations such as tartrazine (yellow dye) may also be responsible.
• Many infections can cause urticaria. Viral upper respiratory infections are a common cause, especially in children. A number of bacterial and fungal infections can also cause hives.
• Drugs that commonly produce urticaria include antibiotics (e.g. penicillins, sulphonamides), pain medications (e.g. aspirin, codeine), sedatives and diuretics. It is important to realise that virtually any medicine can cause hives. Thus, over the counter medications such as vitamins, antacids, eye and ear-drops, laxatives are potential causes of urticaria. It is important
  for your doctor to be aware of all these preparations that you use.

• The best treatment for hives is to find the cause and remove it.
• While investigating the cause, anti-histamines are given for relief.
• Anti-histamines work best if taken on a regular basis to prevent hives from forming.
• To avoid side effects like drowsiness, non-sedative anti-histamines are available.
• No one anti-histamine is best to everyone, so your doctor may need to try more than one anti-histamine to find what works best for you.
• Oral cortisone preparation may also bring relief in severe cases, but they must be given for a short period of time and not long-term due to their side effects.
• Skin tests are generally not useful.

For appointments to our Dermatology Clinic, please call the Appointment Centre
at Tel: 6850 3333