Hives (Urticaria): 10 Possible Causes You Should Know

Hives, also known as urticaria, are itchy, raised welts that can appear suddenly anywhere on the body. They often fade within a few hours but may reappear in different areas. While many cases are harmless and short-lived, hives can sometimes signal an allergic reaction or an underlying medical condition that requires attention.

Here are 10 possible reasons why you may develop hives.

1. Food Allergies

One of the most common causes of acute hives is a food allergy.

Common triggers include:

• Peanuts

• Tree nuts

• Shellfish

• Fish

• Eggs

• Milk

• Soy

• Wheat

Symptoms often appear within minutes to a few hours after eating the trigger food.

2. Medication Reactions

Certain medications can cause hives, including:

• Antibiotics (such as penicillin)

• Aspirin

• Ibuprofen and other NSAIDs

• Some blood pressure medications

• Certain vaccines (rarely)

Never stop a prescribed medication without consulting your healthcare provider unless you are experiencing a medical emergency.

3. Viral Infections

Many cases of hives are triggered by viral infections rather than allergies.

Examples include:

• The common cold

• Influenza

• COVID-19

• Viral stomach infections

Children are especially likely to develop hives during or shortly after viral illnesses.

4. Insect Bites and Stings

Bee stings, wasp stings, mosquito bites, and fire ant bites may trigger localized or widespread hives in sensitive individuals.

Most reactions are mild, but severe allergic reactions require immediate medical attention.

5. Physical Triggers

Some people develop hives after exposure to physical factors such as:

• Cold temperatures

• Heat

• Sunlight

• Pressure from tight clothing

• Exercise

• Sweating

• Water (rarely)

These are known as physical urticarias.

6. Stress

Emotional stress does not directly cause allergies, but it can worsen or trigger hives in some people.

Stress management techniques, adequate sleep, and regular exercise may help reduce flare-ups for some individuals.

7. Chronic Spontaneous Urticaria

If hives occur most days of the week for more than six weeks, the condition is called chronic spontaneous urticaria.

In many cases, no specific trigger is identified.

A healthcare provider may recommend antihistamines or other treatments depending on symptom severity.

8. Autoimmune Conditions

Some autoimmune diseases have been associated with chronic hives, including:

• Autoimmune thyroid disease

• Lupus

• Rheumatoid arthritis

Not everyone with chronic hives has an autoimmune disorder, but further evaluation may be appropriate if symptoms persist.

9. Contact with Irritants

Skin contact with certain substances may trigger hives in sensitive people, such as:

• Latex

• Animal dander

• Certain plants

• Cosmetics

• Cleaning products

• Fragrances

Avoiding the trigger often helps prevent future episodes.

10. Rarely, a Sign of a More Serious Condition

Although uncommon, persistent or recurrent hives may occasionally be associated with:

• Chronic infections

• Hormonal disorders

• Certain inflammatory diseases

• Rare underlying medical conditions

If hives continue for weeks or recur frequently, seek medical evaluation to identify possible causes.

When Are Hives a Medical Emergency?

Seek immediate emergency care if hives occur together with:

• Difficulty breathing.

• Wheezing.

• Swelling of the lips, tongue, or throat.

• Trouble swallowing.

• Dizziness or fainting.

• Rapid heartbeat.

These symptoms may indicate anaphylaxis, a life-threatening allergic reaction that requires urgent treatment.

How to Relieve Mild Hives

For uncomplicated hives, you may find relief by:

• Avoiding known triggers.

• Applying cool compresses.

• Wearing loose-fitting clothing.

• Keeping the skin cool.

• Taking a non-drowsy antihistamine if recommended by your healthcare provider or pharmacist.

• Avoiding scratching, which can worsen irritation.

Can Hives Be Prevented?

You may reduce your risk by:

• Keeping a diary of foods and possible triggers.

• Reading food labels carefully if you have allergies.

• Managing stress.

• Treating infections promptly.

• Avoiding medications that have previously caused reactions, unless advised otherwise by a healthcare professional.

The Bottom Line

Hives are a common skin reaction that can result from allergies, viral infections, medications, insect bites, physical triggers, stress, or chronic medical conditions. Most cases are temporary and resolve within a few days, but hives that persist for more than six weeks or occur with swelling of the face, difficulty breathing, or fainting require prompt medical evaluation.

If you experience frequent or unexplained episodes of hives, consult a healthcare professional to identify the underlying cause and determine the most appropriate treatment.