Hives vs. Eczema: What Are the Differences?

Hives and eczema both involve itchy skin rashes and are related to allergies. While they may share some similarities, these two conditions are distinct in their symptoms, underlying causes, and treatment.

This article will discuss the key differences between hives and eczema in their symptoms, causes, diagnosis, and treatment.

Symptoms

Hives, also called uticaria, are red, itchy bumps or welts on the body. Most of the time, hives go away within a few days to weeks, but some people experience chronic hives that last more than six weeks. About 20% of people experience hives at some point in their lives.

Eczema, also called atopic dermatitis, is a chronic skin condition characterized by itchy lesions. Eczema is more common in childhood, affecting 10% to 20% of children, but between 1% and 3% of adults also live with it.

Hives and eczema both involve an itchy rash, but the symptoms aren't identical.

Causes

Hives and eczema are both related to allergies. While they have similar triggers in some cases, the causes of the conditions can differ.

Hives

Acute hives are often the body's reaction to an irritant, which can include allergic reactions. This causes the body to release histamine and other chemicals into the blood stream, leading to itching and other symptoms.

The cause of chronic hives is not well-understood.

Any irritant can trigger hives, but common ones include:

• Foods such as shellfish, fish, peanuts, tree nuts, eggs, milk, and others
• Insect bites
• Animals/animal dander (commonly cats)
• Pollen
• Medications such as penicillin, sulfa, phenobarbital, and aspirin

Hives can also be triggered by:

• Infections
• Illness
• Heat that raises the body temperature, such as hot tubs, fever, or emotional stress
• Cold, often cold wind or water
• Exercise (exercise-induced hives may cause lung obstruction and loss of consciousness and can be serious)
• Pressure on the skin
• Exposure to sunlight or a sunlamp
• Excessive sweating
  

It's common to be unable to pinpoint what caused the hives when there isn't a known allergy.

Eczema

Eczema is a chronic condition, believed to be caused by a combination of genetic and environmental factors. Often people with eczema have a family history of eczema, asthma, and/or hay fever. Genetic mutations that affect the skin barrier cells and immune skin cells can be hereditary (passed down through generations).

Triggers for eczema flare-ups are similar to those that trigger hives, including:

• Certain foods
• Animal dander
• Dust mites
• Sweating
• Skin contact with irritants like certain fabrics, soaps, or cleaners
• Repeated exposure to water
  
• Extreme heat or cold
• Emotional stress

Diagnosis

Both hives and eczema can be diagnosed by a primary healthcare provider, but seeing a board-certified dermatologist or allergist is preferable.

Hives

Hives are typically diagnosed through a visual examination. Occasionally a skin biopsy (removal of a sample to analyze in the lab) or blood tests may be done to confirm an allergic reaction.

Testing for a substance suspected of causing the allergic response may also be done, but specific allergy testing doesn't tend to be useful for most cases of hives.

Eczema

There's no specific test for eczema. Typically, a healthcare provider will:

• Do a physical exam
• Ask about symptoms
• Ask about personal and family medical history, particularly about allergies, hay fever, and asthma
• Ask about potential triggers, such as certain foods or soaps
• Run tests to rule out other possible causes, if warranted
• Make a referral to a specialist such as a dermatologist or allergist if necessary

Treatment

Treatment for eczema tends to be more complex and ongoing than for hives. Both conditions involve trying to identify and avoid triggers.

Hives

Acute hives can go away on their own, but there are some measures you can take to reduce symptoms such as itching, swelling, and discomfort.

• Apply cool, wet compresses to the affected area
• Avoid hot baths and showers
• Wear loose-fitting clothing

Sometimes medical treatment may be necessary under the guidance of a dermatologist, allergist, or healthcare provider. This may include:

• Antihistamines, particularly for recurrent episodes: Some non-sedating antihistamines can help treat hives. Ask your healthcare provider or pharmacist.
• Topical corticosteroids
• Prescription oral medications, if the hives are chronic
  

If you have a severe reaction, particularly if there is throat swelling and/or airway blockage, you may need to have an emergency shot of epinephrine or steroids.

Eczema

The keystone of eczema treatment is skin care and moisturizing. In addition, it's important to keep the skin hydrated during flares and in between.

Fragrance-free ointments or creams with a higher oil content should be applied at least one to three times a day. The best time to moisturize is right after a warm (not hot) bath or shower and gently patting dry.

Applying wet wraps (a treatment that involves a wet layer covered by a dry layer) may help manage itch.

If symptoms don't respond to over-the-counter (OTC) moisturizers and home treatments, your healthcare provider may suggest options such as:

• Topical corticosteroids
• Sedating antihistamines (at night time)
• Non-steroid prescription creams such as Elidel (pimecrolimus), Protopic (tacrolimus), and Eucrisa (crisaborole)
• Oral medications such as corticosteroids or other immunosuppressants
• An injectable biologic medication Dupixent (dupilumab)
• Phototherapy (uses specialized ultraviolet light)
  

Prevention

Hives and eczema can't always be prevented, but learning to avoid the things that trigger them can be helpful in reducing episodes.

If you can determine the cause of your hives or eczema, such as a particular food, avoiding that trigger will reduce the likelihood of having a flare-up or episode. If you can't avoid your triggers, try to manage them, such as keeping your house cool and using gentle soaps and detergents.

In most cases, chronic hives are not allergy-related, so allergy testing tends not to be useful.

Summary

Both hives and eczema cause itchy, red patches on the skin, but they are distinct conditions.

Irritants and allergens such as certain foods, animals, chemicals, weather, and emotional stress can trigger hives or an eczema flare-up if you are sensitive to them.

Avoiding triggers is the best way to manage hives and eczema, but that isn't always possible. If a reaction happens, acute hives usually go away with minimal treatment, but chronic hives and eczema often require a treatment plan.

If your symptoms are severe, particularly if you are having trouble breathing, seek emergency medical attention.