Hives occur when something prompts cells to release histamine, a chemical found in the skin. The histamine causes nearby blood vessels to dilate. Fluid leaks out of the dilated vessels and collects under the skin in a raised, flushed, itchy bump called a wheal or hive. Some wheals look like mosquito bites. Wheals often come in groups and may be as small as pencil erasers or as large as a dinner plate.
Some people know that certain foods or drugs give them hives. For most others, the causes may not be obvious.
Acute hives, or hives that are a reaction to a stimulus, such as a drug, can last for hours or days. Chronic hives, often of unknown cause, can last for weeks or months.
Some foods that occasionally cause hives are peanuts and other nuts, eggs, beans, chocolate, strawberries and other berries, spices, freshwater fish, shellfish, milk, wheat, cheese, and tomatoes.
Drugs that can cause hives include penicillin, sulfa drugs and codeine.
Extensive hive breakouts can be very serious, especially when hives form on the lips and in the throat, interfering with breathing and swallowing. Shock—in which severe swelling, dizziness and even loss of consciousness occur—can accompany widespread hives.
Self-care for hives
Take an oral antihistamine; be aware of drowsiness.
Try a topical over-the-counter Hydrocortisone cream.
Soak in a lukewarm or cool bath with one cup of baking soda or an oatmeal product.
If hives develop after a bee sting or an insect bite, see a health care provider. You may need a prescription kit to counteract the reaction. A kit contains an injectable dose of epinephrine.
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Prednisone Oral solution
Prednisone Oral tablet
Methylprednisolone Sodium Succinate Solution for injection
Methylprednisolone Oral tablet
Doxylamine Succinate Oral solution
Doxylamine Succinate Chewable tablet
Medroxyprogesterone Acetate Suspension for injection [Malignancy]
Diphenhydramine Hydrochloride Oral disintegrating tablet
Progesterone Vaginal insert
Methylprednisolone Acetate Suspension for injection
Fexofenadine Hydrochloride Oral disintegrating tablet
Ethinyl Estradiol, Norethindrone Chewable tablet, Ferrous Fumarate Chewable tablet
Dexchlorpheniramine Maleate Oral solution
Fexofenadine Hydrochloride Oral suspension
Dexchlorpheniramine Maleate Oral tablet, extended-release
Doxylamine Succinate, Tannic Acid Oral suspension
Doxylamine Succinate Oral tablet
Loratadine Oral disintegrating tablet
Carbinoxamine Maleate Oral solution
Brompheniramine Tannate Chewable tablet
Brompheniramine Maleate Oral solution
Norethindrone Acetate Oral tablet
Hydroxyzine Hydrochloride Oral solution
Norethindrone Acetate, Ethinyl Estradiol Oral tablet [Estrogen Replacement/Osteoporosis]
Chlorpheniramine Maleate, Dextromethorphan Hydrobromide, Phenylephrine Hydrochloride Oral drops, solution
Desloratadine Oral syrup
Cetirizine Hydrochloride Chewable tablet
Triamcinolone Acetonide Nasal spray
Estradiol, Levonorgestrel Transdermal patch - weekly
Doxylamine Succinate Oral tablet [Insomnia]
Desloratadine Oral disintegrating tablet
Promethazine Hydrochloride Solution for injection
Promethazine Hydrochloride Rectal suppository
Promethazine Hydrochloride Oral tablet
Hydroxyzine Hydrochloride Solution for injection
Hydroxyzine Pamoate Oral suspension
Diphenhydramine Hydrochloride Solution for injection
Cyproheptadine Hydrochloride Oral tablet
Clemastine Fumarate Oral syrup
Clemastine Fumarate Oral tablet
Cetirizine Hydrochloride Oral syrup
Cetirizine Hydrochloride Oral tablet
Brompheniramine Tannate Oral suspension
Desloratadine Oral tablet
Norgestrel Oral tablet
Norethindrone Oral tablet
Medroxyprogesterone Acetate Suspension for injection [Contraception]
Medroxyprogesterone Acetate Oral tablet
Levonorgestrel Oral tablet [Emergency Contraception]
Levonorgestrel, Ethinyl Estradiol Oral tablet [Emergency Contraception]
Norelgestromin, Ethinyl Estradiol Transdermal Patch - weekly
Ethinyl Estradiol, Etonogestrel Vaginal insert
Estradiol Cypionate, Medroxyprogesterone Acetate Suspension for injection
Mifepristone Oral tablet
Progesterone Oral capsule
Progesterone Vaginal suppository
Progesterone Vaginal gel
Progesterone Oil for injection
Triamcinolone Acetonide Inhaler
Triamcinolone Acetonide Dental paste
Triamcinolone Oral tablet