Hives

Definition

Symptoms

Causes

Hives all over the body are most often caused by a viral infection. Can also be an allergic reaction to a food, drug, or insect bite. Often, the cause is not found. Hives from foods usually resolve in 6 hours.
Hives just in one spot are usually due to skin contact with an irritant. Examples are plants, pollen, food or pet saliva. Localized hives are not caused by drugs, infections or swallowed foods.

First Aid Advice for Anaphylaxis - Epinephrine

Anaphylaxis is a life-threatening allergic reaction.
If you have epinephrine (such as Epi-pen), give it now.
Do this while calling 911.
Over 66 pounds (30 kg): Give 0.3 mg. Epi-Pen.
33-66 pound (15-30 kg): Give 0.15 mg. Epi-Pen Jr.
Less than 33 pounds (15 kg): Give dose advised by your doctor.
Give the shot into the upper outer thigh in the leg straight down.
Can be given through clothing if needed.
Benadryl: After giving the Epi-pen, give Benadryl by mouth. Do this if your child is able to swallow.

Hives and life-threatening allergic reaction to similar substance in the past. (see FIRST AID .)
Trouble breathing or wheezing
Hoarse voice or cough start suddenly
Trouble swallowing, drooling or slurred speech start suddenly
You think your child has a life-threatening emergency

Your child looks or acts very sick
Hives start after a bee sting or high-risk food. High-risk foods include nuts, fish, shellfish, milk, or eggs.
Hives started after taking a prescription medicine
Age under 1 year with hives all over
You think your child needs to be seen urgently

You have other questions or concerns
Hives make it hard to go to school or do other normal activities. (Note: Taking Benadryl for 24 hours has not helped.)
Food could be the cause
Had hives 3 or more times and the cause is not clear
Hives last more than 1 week

Hives Only on One Part of the Body - What You Should Know:

Wash the allergic substance off the skin with soap and water.
If itchy, use a cold pack for 20 minutes. You can also rub the hives with an ice cube for 10 minutes.
Hives just on one part of the body should go away on their own. They don't need Benadryl.
They should go away in a few hours.

Hives All Over the Body - What You Should Know:

Benadryl for Hives All Over the Body:

Give Benadryl 4 times per day for hives all over that itch. No prescription is needed. See Dose Table.
If you only have another allergy medicine at home (but not Benadryl), use that.
Continue the Benadryl 4 times per day until the hives are gone for 12 hours.
Caution: Do not use if age is under 1 year. Reason: Benadryl is a sedative. Give your doctor a call for advice.

Hives Caused by Foods:

Foods can cause widespread hives.
Sometimes, the hives are just around the mouth.
Hives from foods usually last just a short time. They often are gone in less than 6 hours.

Cool Bath for Itching:

To help with the itching, give a cool bath. Do this for 10 minutes. (Caution: Avoid causing a chill).
Can also rub very itchy spots with an ice cube for 10 minutes.

Get Rid of Allergens:

Stay Away from Allergens:

If you know what is causing the hives, avoid this substance. An example is certain foods.
Help your child stay away from this allergen in the future.

Return to School:

Hives cannot be spread to others.
Your child can go back to school once feeling better. The hives shouldn't keep him from normal activities.
For hives from an infection, can go back after the fever is gone. Your child should feel well enough to join in normal activities.

What to Expect:

Call Your Doctor If:

Author and Senior Reviewer: Barton D. Schmitt, M.D.