Hives vs. Rash: Experts Explain the Differences

If you’ve ever been diagnosed with an inflamed, itchy scalp, eczema, only to have your dermatologist tell you it’s actually psoriasis, you’re not alone. These two conditions are extremely similar in appearance and have almost identical symptoms, but occur for completely different reasons. The same can be said for hives and rashes.

It can be very difficult for the untrained eye to differentiate a skin rash from hives due to appearance and symptoms. Although they are similar, it is important to know their differences in order to properly treat them and get rid of the itching and redness that you experience.

To help you better understand whether you’re dealing with a rash or hives, we asked two dermatologists to explain the differences and provide insight into why they occur and how to treat them.

Experts featured in this article

Christina Collins, MD, FAAD, is a board-certified dermatologist in Austin, Texas.

Mara Weinstein Velez, MD, FAAD, is a board-certified dermatologist in New York City.

What is urticaria?

Urticaria, also known as urticaria, develops on the skin as an immune response to a pathogen. These are raised, itchy welts that appear on the skin. They can vary in size and color and appear anywhere on the body, especially on the arms, legs, torso and throat, often suddenly. However, depending on your skin tone, they may look different. In people with fair skin, the hives may appear red or even pink, while in people with darker skin, the hives may appear the same color as their skin. Regardless of color, scars “can change shape, move, disappear, or reappear within hours,” board-certified dermatologist Christina Collins, MD, FAAD, tells PS.

Hives are usually caused by an allergic reaction in which the immune system releases histamine in response to a trigger. “Common triggers include certain foods such as shellfish, nuts and eggs, medications such as antibiotics or NSAIDs, insect bites, and environmental factors such as pollen or pet dander,” says Dr. Collins. When hives are caused by an allergic reaction, it may be accompanied by a variety of other symptoms, such as shortness of breath, dizziness, trouble breathing, facial swelling, and vomiting.

“In some cases, hives can be caused by non-allergic causes, including stress, infections, heat, cold and pressure on the skin.”

What is a rash?

Hives are actually a type of rash. However, not all rashes are hives. “Skin rashes occur as a result of a compromised skin barrier, a reaction to medications, viral illnesses, contact dermatitis, and more,” says board-certified dermatologist Mara Weinstein Velez, MD, FAAD. “The rashes usually look scaly and “irritated” on the skin and are red or pink in color. Many of them cause itching, but some can also cause a burning sensation.”

For people with dark skin tones, you may notice bumps that are the same color as your skin or slightly darker. They may even appear to have a purple tint. Because they have the ability to blend into your skin so well, it’s important to keep an eye out for any changes in texture, itching, or irritation.

Dr. Collins says a rash is any noticeable change in the appearance of the skin, and its causes can include viral and bacterial fungal infections, irritants from soaps or detergents, and underlying conditions such as eczema or psoriasis. Medicines, heat and friction can also cause a rash.

Hives vs Rash

“The main difference between hives and a rash is the nature and appearance of the skin reaction,” says Dr. Collins. “Hives are raised, itchy welts that usually appear and disappear quickly, often within 24 hours.” She explains that they tend to change shape and can disappear for a few hours before reappearing on another part of your body. Often, after disappearing, they do not leave lasting changes on the skin.

On the other hand, the rash tends to last longer. “They may appear as patches of red, flaky, or inflamed skin and may include symptoms such as burning, pain, or peeling, depending on the cause,” says Dr. Collins. “Although both hives and rashes can be itchy, the rash is less likely to move quickly or change appearance like hives.”

Depending on the cause and source of the rash, there may be specific places on your body where it will appear. “For example, a hairdresser may get a rash on their hands from touching hair dye all day long. It is considered a contact dermatitis type rash, so it is limited to the hands,” says Dr. Weinstein Velez. “If you swallow a drug that you’re allergic to, a rash usually appears all over your body because it was swallowed and spread through the bloodstream.”

If your rash is due to an infection caused by something like a tick bite, the rash will appear on your arms, legs, back, or stomach in a bullseye shape. “Rashes come in many different shapes and patterns; Dermatologists have been trained for years to recognize these patterns in order to treat patients,” says Dr. Weinstein Velez.

Treatment of urticaria

When treating hives, the focus is usually on reducing symptoms and treating the underlying cause. Topical and oral antihistamines, such as cetirizine or diphenhydramine, “are often used to block the release of histamine and relieve itching and swelling,” says Dr. Collins. “In more severe or chronic cases, your doctor may prescribe corticosteroids or stronger medications such as biologics.”

Biologics are drugs made from proteins and genes that are often used to treat skin conditions such as eczema, psoriasis, and hives. Likewise, corticosteroids treat the same conditions and reduce skin inflammation.

Medicines such as Benadryl and Zyrtec help make hives go away faster and also help relieve itching. While they can certainly help with hives, the key to preventing them is avoiding the triggers. “In cases where the allergen is known, patients may need to carry an epinephrine injector (EpiPen) in case of emergency,” says Dr. Collins.

Treatment of the rash

Treatment options for rashes depend on the cause and source of the rash. The rash may occur due to an allergic reaction or irritant. Topical treatments are usually used to soothe and soothe the rash. “For allergic or irritant rashes, treating the cause and using topical corticosteroids or antihistamines can help reduce inflammation and itching,” says Dr. Collins. “Moisturizers and emollients are often used to soothe dry, irritated skin.”

Antifungal creams, antibiotics, or antiviral medications may be needed for rashes caused by infections. Conditions such as eczema or psoriasis may “require long-term treatment, including prescription creams, oral medications, or light therapy,” says Dr. Collins. “It is important to determine the underlying cause of the rash to ensure proper treatment.”

When to see a doctor

If you have a rash or hives, try an over-the-counter option, such as a topical or oral antihistamine, which can help soothe the skin and reduce the problem.

If you have trouble treating it on your own, you can contact your dermatologist or healthcare provider. They can give you a proper diagnosis and develop an effective treatment plan, which may include prescribing biologic drugs or corticosteroids.

Sydney Wingfield has been working as a freelance beauty and health writer for six years. She writes for Women’s Health, Marie Claire, Glamor and other publications and loves covering all things skincare, makeup and hair.