Hives (the common term for urticaria), are pink or red itchy rashes that may appear as blotches or raised red lumps (wheals) on the skin. They range from the size of a pinhead to that of a dinner plate. When hives first start to appear, they can be mistaken for mosquito bites.
Swellings usually disappear within minutes to hours in one spot, but may come and go for days or weeks at a time, sometimes longer. In most cases, hives are not due to allergy and they can be effectively treated with a non-drowsy antihistamine. When hives occur most days for more than six weeks, this is defined as chronic (ongoing) urticaria, which may require additional medication.
- Hives are common – up to 20 per cent of people develop hives at some time during their life.
- Hives can also cause deeper swellings in the skin and mucosa called angioedema. These swellings are often bigger, last longer, may itch less, sometimes hurt or burn and respond less well to antihistamines. Angioedema most frequently affects the face and lips.
- Although hives and facial swelling can be uncomfortable and cosmetically embarrassing, they are not usually dangerous.
- In most cases, hives are not due to allergy. While a clear cause is not obvious in many cases, triggers may include: infection (a virus is usually the most common cause), cold (ice, cold water/air), and pressure on the skin or scratching. Contact allergy to plants or animals can also cause hives.
- An allergic cause for hives should be suspected if episodes are rare, short-lived and occur under specific circumstances, for example ,always within two hours of a particular meal.
- Ongoing hives lasting days at a time are almost never allergic in origin, with the exception of some cases of allergy to medicines. Stress is a very rarely the cause of hives, but may make the symptoms worse.
Chronic urticaria (CU)
CU is defined as hives that occur most days for more than six weeks. Generally, this is a mild condition that responds well to simple therapy. Occasionally, the hives can be severe and interfere with quality of life. This may require referral to a clinical immunologist, allergist or dermatologist to guide therapy. Unlike CU in adults, in children this is rarely associated with autoimmune diseases and blood testing is not indicated in most cases.
Generally, testing is not necessary in the absence of other symptoms or signs. Allergy testing is rarely indicated and often adds unnecessary confusion and stress.
- Avoid aggravating factors if identified – for example, the cold and excessive heat.
- Medications can help.
- Second generation antihistamines (desloratidine, cetirizine, loratadine and fexofenadine) can be given regularly if hives occur daily. It may be necessary to increase the daily dose for refractory rash under the supervision of your doctor.
- AVOID corticosteroids (e.g., prednisone) as there is a much higher side-effect profile and no benefit.
- H2 – blockers (e.g., ranitidine) can be helpful in some cases of CU.
- Specialist medications are available for severe cases in certain circumstances after consultation with a clinical immunologist or dermatologist.
- Diets – there is no evidence to suggest special diets have a role in managing children with acute or chronic urticaria
Patients who have had an episode of urticarial (hives) and/or angioedema are likely to have subsequent episodes.
Acute urticarial: Generally, this is a brief and self-limiting condition that lasts a few days to weeks. There is rarely any risk of a severe episode involving the breathing or circulation (anaphylaxis).
Chronic urticarial: This can last for months to years. Recent reports have suggested a 10 per cent annual resolution rate, but this may be an underestimate. For prolonged daily urticarial, regular antihistamines are important and safe to be taken daily for years, if necessary.
If it’s not an emergency but you have any concerns, contact 13 Health (13 43 2584). Qualified staff will give you advice on who to talk to and how quickly you should do it. You can phone 24 hours a day, seven days a week.
In an emergency, always contact 000 for immediate assistance.