Hives

What are hives?

Hives are a very itchy rash usually caused by an allergic reaction. Hives look like raised pink spots with pale centers on the skin. The spots range from 1/2 inch to several inches wide (hives often look like mosquito bites). The spots may be different shapes. The spots rapidly and repeatedly change in location, size, and shape. Giant hives are called angioedema. This can cause large swelling beneath the skin, especially of the face.

What is the cause?

Widespread hives usually are a reaction to a viral infection. Less commonly they are an allergic reaction to a food, medicine or bee sting. Often the cause is not found (more than 30%). Hives on just one part of the body (localized) are usually due to skin contact with plants, pollen, food, or pet saliva. Localized hives are not an allergy and not caused by drugs, infections, or swallowed foods. Hives are not contagious.

Rarely, hives may also be caused by:

• Exposure to cold air or water
• Exposure to sunlight
• Becoming overheated from exercise or a hot shower

How long do they last?

More than 10% of children get hives. Most children who develop hives have them only once. The hives come and go for 3 or 4 days and then mysteriously disappear.

Large swellings are common around the eyes, lips, and genitals if hives occur there.

Some young children become sensitized to mosquito or flea bites. They develop big hives (called papular urticaria) at the sites of old and new bites. These hives may last for months.

How can I take care of my child?

• Antihistamine medicine

  The best drug for hives is an antihistamine. An antihistamine won't cure the hives, but it will reduce their number and relieve itching.

  Benadryl (diphenhydramine) is the most commonly used drug for hives, and is available without a prescription. The main side effect of this drug is drowsiness in some people. Other antihistamines (for example, store brands of any drug for hay fever) will also help. When you give Benadryl, give it 3 to 4 times a day until the hives are gone for 12 hours. Use the dosage given on the product. Benadryl is approved over age 1 for allergic symptoms.

  Use the drug recommended by your child's healthcare provider.

• Itching

  For flare-ups of itching, give your child a cool bath without soap for 10 minutes. (Caution: avoid any chill). Put a cold washcloth or ice cube on itchy areas for 10 minutes. Avoid heat or rubbing.

• Avoidance and showers

  Avoid anything you think might have caused the hives. For hives triggered by pollen or animal contact, take a cool shower or bath. For localized hives, wash the allergic substance of the skin with soap and water. Localized hives usually disappear in a few hours and don't need Benadryl. Avoid heat or rubbing, which makes hives worse.

• Common mistakes in the treatment of hives

  Many parents wait to give the antihistamine until new hives have appeared. This means your child will become itchy again. The purpose of the medicine is to keep your child comfortable until the hives go away. Therefore, give the medicine regularly until you are sure the hives are completely gone.

  Hives are not contagious and your child can be with other children.

When should I call my child's healthcare provider?

Call IMMEDIATELY if:

• Breathing or swallowing becomes difficult.
• Your child starts acting very sick.

Call during office hours if:

• Most of the itch is not relieved after your child has been taking an antihistamine for 24 hours.
• The hives last more than 1 week.
• You have other concerns or questions.