Hives, also known as urticaria, are circumscribed swellings on the skin that often are itchy. Hives occur usually when mast cells in the skin release histamine, a chemical that causes tiny blood vessels to leak fluid. When this fluid accumulates in the skin, it forms the swellings that we recognize as hives.
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Hives can be triggered by physical factors such as heat, cold, exercise, sunlight, stress, sustained pressure on a skin areas, such as from a belt or shoulder strap, or a sudden increase in body temperature (from a fever or a hot bath or shower) or from an irritating chemical, cosmetic or soap applied to the skin.
Hives also can be one symptom of a whole-body (systemic) allergic reaction by inhaling, ingesting or injecting the followings:
Inhaled — Pollens, animal dander, molds
Injected — Insect stings or bites, especially bee stings, or injected medication
Ingested — Foods (tree nuts; fish and shellfish; dairy products; legumes, especially peanuts), food additives, medications such as penicillin or aspirin
It only affects about 20% of people in the United States at some time in life, occurring in people aged 20 to 30. In rare cases, allergic reactions that trigger hives set off a chain reaction throughout the body – this may lead to a life-threatening condition called anaphylaxis. Sometimes, hives may even last for six weeks or more. In that case, it’s a serious condition called chronic (or idiopathic) urticaria.
Hives appear as swellings on the skin, sometimes pink or red and surrounded by a red blotch. Typically it’s round or oval in appearance and often itchy.
Hives vary in size – some may blend to form larger areas of swelling.
It can affect skin on any area of the body, especially the trunk, thighs, upper arms, and face.
Most individual hives fade quickly, but new ones appear every 24 to 72 hours if the person continues to be exposed to the environment or substance that triggered the hives.
If hives are an early sign of a whole-body reaction, other symptoms to look for include swelling of the tongue, lips or face; wheezing; dizziness; chest tightness; and breathing difficulties. In all these cases you need immediate medical care.
Doctor asks about the history of your allergic reactions, and also about your recent exposure to pets, plants, insects or new foods or medications. During a physical examination, your doctor usually can distinguish between hives and other types of skin rashes. If the condition occurs frequently, your doctor asks you for blood tests or perform skin testing for allergies. If your doctor suspects that you are undergoing anaphylaxis, you need to undergo the prescribed treatment.
Individual hives usually fade within eight to 12 hours, but it may even last for a few weeks to months. Chronic urticaria may last for six months or more.
You can prevent hives by identifying and avoiding the particular circumstance or substance that triggered your skin reaction. If your doctor determines that you are allergic to insect venom, you will be advised to keep an epinephrine kit for emergency injections to prevent anaphylaxis. It’s better to keep medication in a convenient place so that you can immediately reach out to it in case of an emergency.
The relieve the symptoms, the doctor may advise you to apply calamine lotion and take an antihistamine medication, such as chlorpheniramine (Chlor-Trimeton), clemastine (Tavist) or diphenhydramine (Benadryl). If these medications are not effective, you may be given a prescription medication such as cyproheptadine (Periactin), azatadine (Optimine) or hydroxyzine (Atarax or Vistaril).
Note: Always consult your doctor and then take a suitable medicine as per your allergic skin reaction.