What Are Hives, and How Are They Treated?

Hives (urticaria) are a common skin reaction that causes bumps, raised patches, or both. They are one way the body responds to an allergen or trigger. Reactions can be uncomfortable but aren’t typically serious and resolve on their own. Most people find relief with allergy medications.

What Do Hives Look Like?

Hives appear as raised welts (also called welts or wheals) on the skin. They appear slightly raised above the skin and may be skin-colored. If you press them, the center of a red hive turns white. Hives are usually surrounded by erythema or skin flushing that can last from a few minutes up to 24 hours.

Skin swelling or angioedema can also occur with hives.

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How to Determine If You Have Hives

It’s not always obvious if you have a rash or hives, or why. Determining if you have hives can be done with testing and diagnosis. 

See a board-certified dermatologist if hives:

• Are caused by an allergy 
• Cover a large area of your body
• Persist longer than six weeks

A healthcare provider can help you determine if you need to see an allergy specialist.  

Tests for hives include:

• Blood tests to check for antibodies fighting allergens
• Skin-prick tests

Even with testing to diagnose hives, it may not be possible to determine the cause. Estimates show about half of people who have chronic hives never learn the cause.

How to Find Relief

Even if you do not know the cause, you can find relief for hives at home. Experts recommend the following methods:

• Apply a cold compress (ie., ice wrapped in cloth) to itchy areas several times a day.
• Avoid overheating.
• Find ways of relaxing (stress makes hives worse).
• Use a nonprescription anti-itch medication like an antihistamine. 
• Wear loose-fitting, cotton/breathable clothes.

Other treatment approaches may be necessary. For people with chronic hives, an immune system medication Xolair (0malizumab) may be used. If these medications do not work, your dermatologist will discuss other medications to try.

Potential Causes

Allergic Reactions

Around 20% of people will experience hives at some point in their lifetime, commonly caused by an allergic reaction. During an allergic reaction, your body releases chemicals called histamine into the blood. This is an immune system response resulting in swelling, itching, and other symptoms of hives.

Hives can appear from allergic reactions to food, medications, and insect bites such as bee or wasp stings.

Common food allergens associated with hives are:

• Egg
• Milk
• Peanut
  
• Shellfish

Medications associated with hives include:

• Antibiotics
• Aspirin
• Nonsteroidal anti-inflammatory drugs (NSAIDs)
• Opiates

Pet dander, pollen, and latex can also trigger hives in people with those specific allergies.

Physical Triggers

Physical triggers that have nothing to do with allergies can also cause hives. Physical triggers include:

• Emotional stress like anxiety
• Excessive perspiration or sweating
• Exercise
• Exposure to sun, water, or extreme cold
• Pressure or tight clothing

Infection

Infections can also trigger an immune system resulting in hives.

Acute viral infections associated with hives include:

• Infectious mononucleosis (mono)
• Upper respiratory infections
• Urinary tract infections (UTIs)
• Viral hepatitis

Acute bacterial infections that can trigger hives include:

• Dental abscess
• Mycoplasma infections
• Sinus infections (sinusitis)

Underlying Health Conditions

Underlying health conditions, especially those affecting the immune system, can also lead to hives. The conditions associated with hives include lupus and other autoimmune diseases, and leukemia.

Chronic Hives

With chronic hives, it’s even more difficult to pinpoint the exact cause. Experts suggest an autoimmune cause is likely, but more research is needed to better understand the connection.

Chronic hives are associated with autoimmune disorders, but also:

• Chronic infection such as Helicobacter pylori
• Thyroid disease
• Celiac disease
• Vitiligo
  

Summary

Hives are little bumps caused by an immune system reaction. They can be short-term or chronic, and typically resolve on their own. Relief can be found from medications, anti-itch products, and at-home remedies. Avoiding triggers is a way to prevent hives. Some reactions can be serious. When in doubt, consult with a healthcare provider or dermatologist.