5 Most Common Causes of Hives

Hives — also known as urticaria — are raised, itchy welts (called wheals) that can vary in size and shape. They often appear suddenly and may be triggered by a range of factors, including allergies, stress, or certain medications. The affected skin may look red or pale, and the welts can shift locations or disappear within hours.

About 20% of people will experience hives at some point in their lives. Here are some of the most common triggers:

• Allergic reactions. Hives are frequently caused by allergic responses to foods such as nuts, shellfish, eggs, and dairy products. In these cases, the immune system releases an antibody called immunoglobulin E (IgE), which triggers symptoms. Certain medications — including antibiotics, nonsteroidal anti-inflammatory drugs (NSAIDs), and aspirin — can also provoke hives in sensitive individuals. Latex (found in gloves, rubber bands, or balloons), insect stings from bees or wasps, and pollen exposure during allergy season are additional common triggers.

• Infections. Viral and bacterial infections can lead to hives, particularly in children. Upper respiratory infections, urinary tract infections, and viral illnesses such as the common cold or hepatitis are among the culprits. In some cases, hives develop during the illness or even after it has resolved, as the immune system continues to react.

• Stress and emotional factors. Psychological stress, anxiety, and intense emotions may prompt the body to release histamine, leading to the sudden onset of hives. For some people, even excitement or overwhelming feelings can act as triggers, according to GoodRx.

• Exposure to extreme temperatures. Sudden temperature changes — such as moving from a warm indoor setting into cold air, or swimming in cold water — can spark outbreaks. Heat-induced hives (cholinergic urticaria) and cold-induced hives (cold urticaria) are both well-documented conditions.

• Physical triggers. Direct irritation to the skin can cause hives in susceptible individuals. Tight clothing, pressure from carrying heavy bags, scratching, rubbing, or vigorous exercise may all set off symptoms. This form, known as physical or mechanical urticaria, typically causes red, itchy, or sometimes painful wheals only in the areas exposed to pressure or friction.

Children, women, and Black and Latino individuals are more likely to experience hives. People living in crowded environments or at high altitudes, as well as those with certain underlying medical conditions, may also be more susceptible.

Most cases are mild and clear up on their own within hours to a few days, especially if the trigger is identified and avoided. Over-the-counter antihistamines such as cetirizine (Zyrtec), loratadine (Claritin), or diphenhydramine (Benadryl) are commonly used to ease itching and reduce welts. For persistent or severe cases, a healthcare provider may prescribe stronger antihistamines, corticosteroids, or other medications.

If hives are accompanied by difficulty breathing, throat swelling, or other signs of a severe allergic reaction, seek immediate medical care. These symptoms may signal anaphylaxis, a life-threatening emergency.