Hives
Is this your symptom?
- An itchy rash made up of raised pink bumps
- Hives vary in shape and size
Symptoms of Hives
- Raised pink bumps with pale centers (welts)
- Hives look like mosquito bites
- Sizes of hives vary from ½ inch (12 mm) to several inches (cm) across
- Shapes and location of hives can be different. They can also change often.
- Itchy rash
Causes of Widespread Hives
- Viral Infection. The most common cause of hives all over the body is a viral infection. Research has confirmed this. Other symptoms such as a fever, cough or diarrhea are also present. The hives may last 3 days. This is not an allergy.
- Bacterial Infection. Some bacterial infections can also cause hives. A common example is Strep. Hives are also seen with bladder infections. (UTIs)
- Drug Reaction. An example is a penicillin rash. Most rashes that start while taking an antibiotic are viral rashes. Allergy tests are normal 90% of the time. Only 10% turn out to be a drug allergy.
- Food Reaction. May be an allergy or a coincidence. If the food is a high risk one (such as peanuts), consult an allergist. Hives from foods usually resolve in 6 hours. Hives from infections last for days. Only 3% of hives are due to a food.
- Bee Sting. Widespread hives after a sting may be part of a serious allergic reaction. Need to consult an allergist.
- Anaphylactic Reaction (very serious). The sudden onset of hives with trouble breathing or swallowing. This is a severe allergic reaction to a food or drug. Most often begins within 30 minutes of swallowing the substance. Always within 2 hours of exposure. It can happen even if you have had that food or drug before and did not have a reaction then. Call 911 immediately.
- Unknown. More than 30% of the time, the cause of hives is not found.
Causes of Localized Hives
- Irritants. Hives just in one spot are usually due to skin contact with an irritant. They are not an allergy.
- Plants. Many plants cause skin reactions. Sap from evergreens can cause local hives.
- Pollen. Laying in the grass can cause hives on exposed skin.
- Pet Saliva. Some people get hives where a dog or cat has licked them.
- Food. Some people get hives if a food is in contact with their skin. An example could be a fresh fruit.
- Insect Bite. Local hives are a reaction to the insect's saliva. Can be very large without being an allergy.
- Bee Sting. This is a reaction to the bee's venom. Can be very large without being an allergy.
- Localized hives are not caused by drugs, infections or swallowed foods. These get into the bloodstream and cause widespread hives.
When to Call for Hives
Call 911 Now
Call Doctor or Seek Care Now
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Contact Doctor Within 24 Hours
Contact Doctor During Office Hours
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Self Care at Home
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Call 911 Now
- Previous hives and a life-threatening allergic reaction to a substance in the past and exposure less than 2 hours ago
- Passed out or very weak and can't stand
- Trouble breathing or wheezing
- Hoarse voice or cough start all of a sudden
- Throat or tongue started swelling all of a sudden
- You think you have a life-threatening emergency
Call Doctor or Seek Care Now
- Hives start after eating a high-risk food. High-risk foods include nuts, fish, shellfish, or eggs.
- Hives started after taking a prescription medicine
- Hives started after exposure to something you have had a reaction to before
- Stomach pain or vomiting
- You feel very sick
- You think you need to be seen, and the problem is urgent
Contact Doctor Within 24 Hours
- Hives make it hard to go to work, school or do other activities. Note: taking Benadryl for 24 hours has not helped.
- Hives started after taking an over-the-counter medicine
- Fever or joint swelling is present
- You think you need to be seen, but the problem is not urgent
Contact Doctor During Office Hours
- Food could be the cause
- Had hives 3 or more times in past year with no known cause
- Hives last more than 1 week
- You have other questions or concerns
Self Care at Home
- Mild hives with no other problems
Care Advice for Hives
- Hives Only on One Part of the Body - What You Should Know:
- Most are caused by skin contact with an irritant. Examples are plants, pollen, food or pet saliva.
- Localized hives are not caused by drugs, infections or swallowed foods. They are also not an allergy.
- 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:
- Most widespread hives are caused by a viral infection. This is not due to an allergy. Less than 10% are an allergic reaction to a food, drug, or insect bite. Often, the cause is not found.
- Here is some care advice that should help.
- Allergy Medicine for Hives All Over the Body:
- Give Benadryl 4 times per day for hives all over that itch. No prescription is needed.
- If you only have another allergy medicine at home (but not Benadryl), use that.
- Use an allergy medicine until the hives are gone for 12 hours.
- Caution: allergy medicines can make you feel drowsy. Always follow the advice on the package. Do not take more than the recommended dosage.
- Do not drive, operate machinery or continue to work if you feel drowsy.
- If you are not sure what to take, ask your doctor or a pharmacist.
- 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, take a cool bath. Do this for 10 minutes. Caution: avoid causing a chill.
- You can also rub very itchy spots with an ice cube for 10 minutes.
- Wash Allergens Off Body:
- Take a bath or shower if caused by pollens or animal contact.
- Change your clothes and wash them to remove allergens.
- Stay Away from Allergens:
- If you know what is causing the hives, avoid this substance. An example is certain foods.
- Stay away from this allergen in the future.
- Return to Work or Other Activities:
- Hives cannot be spread to others.
- You can go back to work once you are feeling better. The hives shouldn't keep you from normal activities. Note: you may be drowsy due to allergy medicines.
- For hives from an infection, you can go back to work after the fever is gone. You should feel well enough to do normal activities.
- What to Expect:
- Hives all over from a viral illness normally come and go.
- They may last for 3 or 4 days. Then, they go away.
- Call Your Doctor If:
- Severe hives not better after 2 doses of Benadryl
- Itch not better after 24 hours on Benadryl
- Hives last more than 1 week
- You think you need to be seen
- Your symptoms get worse
And remember, contact your doctor if you develop any of the 'Call Your Doctor' symptoms.
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