This information is approved and/or reviewed by U-M Health System providers but it is not a tool for self-diagnosis or a substitute for medical treatment. You should speak to your physician or make an appointment to be seen if you have questions or concerns about this information or your medical condition. Exención de responsabilidad en Español | Complete disclaimer
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.
Widespread hives are an allergic reaction to a food, medicine, viral infection, insect bite, and other substances. Often the cause is not found. 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 caused by drugs, infections, or swallowed foods. Hives are not contagious.
Rarely, hives may also be caused by:
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.
The best drug for hives is an antihistamine. An antihistamine won't cure the hives, but it will reduce their number and relieve itching.
Diphenhydramine (Benadryl), one of the most commonly used drugs for hives, is available without a prescription. The main side effect of this drug is drowsiness. Other antihistamines (for example, store brands of any drug for hay fever) will also help. Diphenhydramine tends to give better results than other antihistamines. 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.
Your child's drug is __________________________. Give ___________ every ______ hours. Continue the medicine until the hives are completely gone for 24 hours.
Give a cool bath to relieve itching. Put a cold washcloth or ice cube on itchy areas for 10 minutes. Avoid heat or rubbing.
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.
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.
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