Urticaria (Hives)

What is urticaria (hives)?

• Hives are localised, itchy pink swellings (wheals) that can occur on any part of the skin.
• Hives can last from a few minutes to a few hours, before fading away completely within 24 to 48 hours.
• Hives are very common in Singapore.
• Individual wheals usually disappear within 24 hours, though urticaria is a condition that can last for many years.
  
• When urticaria occurs around the loose tissues of the eyes or lips, the tissue may swell excessively. This swelling is called angioedema and it goes away in 24 to 48 hours.
  

What are the causes of urticaria?

• Physical agents (e.g., heat, sweating, exercise, sunlight, pressure, cold)
  
• Medication such as antibiotics (e.g., penicillin, sulphonamides), pain medications (e.g., aspirin, codeine), sedatives and diuretics. Any medication can potentially cause hives, hence please inform your doctor about all your medications, including vitamins, antacids, laxatives, eye and ear drops.
• Viral upper respiratory infections are a common cause, especially in children. A number of bacterial and fungal infections can also cause hives.
• Insect bites
• Internal diseases such as thyroid diseases
• Common foods such as nuts, eggs, fresh citrus fruits, tomatoes and shellfish. Food additives and preservatives such as tartrazine (yellow dye) may also result in hives.

Sometimes, no cause can be found.

How can urticaria be treated?
While it may not be always possible to find the cause of urticaria, keeping track of your flare-ups may help you identify and avoid possible triggers.

Antihistamines are given for relief as the cause of your hives are being investigated. Non-sedating antihistamines are available to avoid side effects like drowsiness. Different antihistamines work differently for different people so your doctor may need you to try more than one antihistamine to find what works best for you. Antihistamines work best if taken on a regular basis to prevent hives from forming.

For severe cases, oral steroids may also bring relief, but they are only given for a short period of time and not long-term due to their side effects such as an increase in blood sugar and blood pressure levels.

Skin tests are not routinely performed in the evaluation of urticaria.

When do you seek medical advice?
Seek medical advice at the Emergency Department immediately if you experience any of the following symptoms while having an episode of hives:

• Swollen tongue
• Wheezing, problems with breathing or swallowing
• Chest tightness
• Giddiness, feeling faint or loss of consciousness
• Abdominal pain, diarrhoea or vomiting
• Feeling unwell