Hives vs. Rashes — How to Spot the Differences, According to Experts

If you've ever self-diagnosed your inflamed, itchy scalp with eczema just to have your dermatologist tell you it's actually psoriasis, you're not alone. The two conditions are extremely similar in appearance and have almost identical symptoms, but they appear 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 vs. hives due to the conditions' appearance and symptoms. While they're similar, it's important to know their differences to properly treat them and get rid of any of the itchiness and redness you're experiencing.

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

Kristina Collins, MD, FAAD, is a board-certified dermatologist based in Austin, TX.

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

What Are Hives?

Hives, otherwise known as urticaria, develop on the skin as an immune response to a trigger. They are raised, itchy welts that appear on the skin, and 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. Those with a lighter complexion may notice their hives appear red or even pink, while those with darker skin may have hives that are their skin color. No matter the color, the welts "can change shape, move around, and disappear or reappear over hours," board-certified dermatologist Kristina Collins, MD, FAAD, tells PS.

Hives are usually caused by an allergic reaction where the immune system releases histamine in response to a trigger. "Common triggers include certain foods such as shellfish, nuts, and eggs, medications like antibiotics or NSAIDs, insect stings, and environmental factors like pollen or pet dander," Dr. Collins says. When hives are caused by an allergic reaction, it's possible that they are accompanied by a slew of other symptoms, such as shortness of breath, dizziness, trouble breathing, puffiness in the face, and vomiting.

"In some cases, hives can be triggered by nonallergic causes, including stress, infections, heat, cold, and pressure on the skin."

What Are Rashes?

Hives are actually a type of rash. However, not all rashes are hives. "Rashes occur on the skin as a result of a compromised skin barrier, drug reactions, viral illness, contact dermatitis, and many more," says board-certified dermatologist Mara Weinstein Velez, MD, FAAD. "Rashes typically look scaly and 'angry' on the skin and have a red or pink color. Many are itchy, but some can also have a burning sensation."

For those with dark skin tones, you may notice raised bumps that are your skin color or slightly darker. They may even appear to have a purple tint to them. Because they have the ability to blend into your skin so well, it's important to look out for any changes in texture, itchiness, and irritation.

Dr. Collins says that a rash refers to any noticeable change in the skin's appearance, and its causes can include viral and bacterial fungal infections, irritants from soaps or detergents, and underlying health conditions such as eczema or psoriasis. Medications, heat, and friction can also trigger rashes.

Hives vs. a Rash

"The main difference between hives and a rash is the nature and appearance of the skin reaction," Dr. Collins says. "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 and appear again on another part of your body. Oftentimes, they leave no lasting skin changes once they subside.

On the other hand, rashes tend to linger longer. "They can present as patches of red, scaly, or inflamed skin and may include symptoms such as burning, pain, or peeling, depending on the cause," Dr. Collins says. "While both hives and rashes can be itchy, rashes are less likely to move or change appearance rapidly like hives do."

Depending on the cause and source of a rash, there can be specific places where it will appear on your body. "For example, a hairdresser can develop a rash on the hands from touching hair dye all day, that is considered a contact-dermatitis-type rash, so it's limited to the hands," Dr. Weinstein Velez says. "If you ingest a drug that you're allergic to, then the rash typically appears all over the body because it was ingested and spread through the bloodstream."

If your rash is related to an infection from something like a tick bite, the rash will appear on your arms, legs, back, or abdomen in a bullseye-type pattern. "Rashes come in many different shapes and patterns; dermatologists are trained over years to be able to recognize these patterns in order to treat patients," Dr. Weinstein Velez says.

Treatments For Hives

When treating hives, the focus is typically on reducing symptoms and addressing the underlying cause. Topical and oral antihistamines such as cetirizine or diphenhydramine "are often used to block histamine release and relieve itching and swelling," Dr. Collins says. "For more severe or chronic cases, a doctor may prescribe corticosteroids or stronger medications like biologics."

Biologics are medications derived from proteins and genes and are often used to treat skin conditions such as eczema, psoriasis, and hives. Similarly, corticosteroids treat the same conditions and reduce inflammation in the skin.

Medications like Benadryl and Zyrtec help speed the resolution of hives and also help with the itch. While these can certainly help with hives, avoiding triggers that cause them is key to prevention. "In cases where an allergen is known, patients may need to carry an epinephrine injector (EpiPen) for emergencies," Dr. Collins says.

Treatments For Rashes

Treatment options for rashes are tailored to the cause and source of the rash. You can have a rash from an allergic reaction or from an irritant. Usually, topical treatments are used to help soothe and calm the rash. "For allergic or irritant rashes, removing the trigger and applying topical corticosteroids or antihistamines can help reduce inflammation and itching," Dr. Collins says. "Moisturizers and emollients are often used to soothe dry, irritated skin."

Antifungal creams, antibiotics, or antivirals may be required for rashes caused by infections. Conditions like eczema or psoriasis may "require long-term management, including prescription creams, oral medications, or light therapy," Dr. Collins says. "It's important to identify the underlying cause of a rash to ensure proper treatment."

When to See a Doctor

If you're dealing with either a rash or hives, trying out an over-the-counter option, such as a topical or oral antihistamine, may help soothe your skin and diminish the issue.

If you're having trouble treating it on your own, you can reach out to your dermatologist or healthcare provider. They will be able to provide you with a proper diagnosis and an effective treatment plan that may include a prescription biologic or corticosteroids.

Sydney Wingfield has been a freelance writer in the beauty and wellness space for six years. She has written for Women's Health, Marie Claire, Glamour, and other publications and loves to cover all things skin care, makeup, and hair.