Hives (urticaria): itchy welts, causes, relief and when they are an emergency

Hives can be part of a severe allergic reaction (anaphylaxis), which is life-threatening. Call 911 right away if hives come with any of these signs. If the person has an epinephrine auto-injector, help them use it while help is on the way. See when to go to the ER.

• Swelling of the lips, tongue, face or throat
• Trouble breathing, wheezing or a tight throat
• A hoarse or whispery voice, or trouble swallowing
• Dizziness, fainting or feeling about to faint
• Nausea or vomiting along with the hives

Hives (urticaria) are red or skin-colored raised welts with clear edges that itch. They can grow, join together, change shape, and disappear and come back within minutes or hours.

Often they are an allergic reaction to foods (such as shellfish or nuts), medicines, insect bites, pet dander or pollen. They also happen without an allergy: from infections, stress, intense cold or sun, sweating, exercise or water. In Puerto Rico’s heat, sweat and tight clothing can make them worse. Often no cause is found.

Hives that last more than 6 weeks are called chronic hives. A cause is rarely found, and most cases go away on their own within a year.

Doctor online 24/7 for hives: video doctor visits 24/7 — book online and choose your time right away. Every day, any time (Puerto Rico time). This is how you see a doctor online with us.

Hives are handled in a doctor visit, the same price for every age, with no membership. You pay by card when you request the visit, and you get a full refund if the clinic can’t see you. A doctor’s note after your visit is included. See all prices.

What you usually see:

• Raised, red or skin-colored welts that itch
• Welts with clear edges that grow and merge
• Welts that change shape, disappear and come back within minutes or hours

Mild hives often go away on their own. For the itch, avoid hot baths or showers and tight clothing. The doctor may suggest an antihistamine, such as cetirizine or diphenhydramine, and chronic hives may need a prescription medicine, such as hydroxyzine, a prescription antihistamine that causes drowsiness. For a severe flare, the doctor may prescribe a steroid pill such as prednisone for a few days. If you know what set them off, avoid it.

If hives last more than 6 weeks or keep coming back, the doctor decides whether a lab test would help: we give you an order for lab work at a lab near you and go over the results with you in a follow-up visit to review results.

If your hives came with face swelling or trouble breathing, even if it has passed, tell the doctor: you may need to carry epinephrine and see an allergy specialist.

People call two different things a skin allergy. Hives are welts that move around: each one fades within hours and new ones appear elsewhere. Contact dermatitis is red, itchy skin, sometimes with small blisters, right where something touched it (a soap, a fragrance, nickel in jewelry, latex); it usually appears 24 to 48 hours after contact and lasts 2 to 3 weeks.

If yours looks more like the second, see contact dermatitis and eczema. The doctor can tell the two apart on video and tells you what to avoid. To compare every form of skin allergy, including angioedema, see our guide.

If your problem is sneezing and an itchy nose, see allergy treatment. If your rash isn’t welts that come and go, see skin rash. If your skin itches but you see no welts, see itchy skin.