medical hives

Hives (Urticaria)

Hives are welts on the skin that often itch and may be cause by an allergy. They can appear on any part of the skin and vary in size from as small as a pen tip to as large as a dinner plate. Hives will occur within minutes to 2 hours of exposure to a trigger. A hive will go away in 24 hours or less but new hives can continue to form for days or even weeks. If they last longer than 6 weeks, it is termed chronic urticaria. Sometimes these hives go away on their own within a year. Angioedema is a condition where the eyelids and lips dramatically swell. If this occurs, the person needs emergency care right away. For most people, hives are not serious. Children may outgrow the allergies that cause their hives. If the hives remain or becomes severe, it’s important to get medical care. If you have hives and trouble breathing or swallowing, get emergency care right away.

Signs and symptoms:
◦ Slightly raised, pink or red swellings
◦ Welts that occur alone, in a group, or connect over a large area
◦ Skin swelling that subsides or goes away within 24 hours at 1 spot but may appear at another spot
◦ The lesions usually itch but may sting or hurt

What causes hives?
◦ Allergic reactions can trigger hives. Some common triggers include:
◦ Foods: Fruits (especially citrus fruits), milk, eggs, peanuts, tree nuts, and shellfish
◦ Medicines (over-the-counter, herbals or prescription)
◦ Pollen
◦ Insect bites and stings
◦ Touching something you are allergic to, such as latex
◦ Allergy shots
◦ Other causes of hives are
◦ Infections, including colds and infections caused by some bacteria or fungi
◦ Some illnesses, including vasculitis, lupus, and thyroid disease
◦ Exposure to sun (solar urticaria), heat, cold, or water
◦ Exercise
◦ Stress (cholinergic urticaria)
◦ Pressure on the skin, such as from sitting too long
◦ Contact with chemicals
◦ Scratching the skin (dermatographism)

◦ When a patient has hives, a dermatologist can often make the diagnosis by looking at the skin. Finding the cause of hives can be a challenge, especially if they have been occurring for more than 6 weeks
◦ Your dermatologist will review your health history in detail, ask questions, and do a physical exam. Some of the medications that may be prescribed:
◦ Non-drowsy antihistamine or drowsy antihistamines
◦ Topical corticosteroid creams or ointments
◦ Dapsone
◦ Montelukast
◦ Omalizumab (for chronic urticaria)
◦ Blood tests, allergy tests (prick tests) or a routine small skin biopsy may be recommended
◦ If there is mouth or lip swelling, or difficulty breathing, call 9-1-1. You may need a shot of epinephrine or other urgent treatment(s)