- An itchy rash made up of raised pink bumps
- Most often, rash is very itchy
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 viral infections. 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 an allergic food or drug. Most often begins within 30 minutes of swallowing the substance. Always within 2 hours of exposure.
- Unknown. Over 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. Playing 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 children get hives if a food is rubbed on the skin. An example could be a fresh fruit. Some babies get hives around their mouth from drooling a new food.
- 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.