If you have already self-diagnosed your inflamed and itchy scalp with eczema just for your dermatologist to tell you it’s actually psoriasisyou are 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 between a rash and hives due to the appearance and symptoms of these conditions. Although they are similar, it is important to know their differences to treat them correctly and eliminate the itching and redness you experience.

To help you better understand whether it’s a rash or hives, we asked two dermatologists to explain the differences and explain why they occur and how to treat them.

Experts featured in this article

Kristina CollinsMD, FAAD, is a board-certified dermatologist based in Austin, Texas.

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

What are hives?

Hives, also known as hives, develop on the skin as an immune response to a trigger. These are raised, itchy marks 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 be different. Those with lighter skin tones may notice that their hives appear red or even pink, while those with darker skin may have hives that are the same color as their skin. Regardless of their color, the marks “can change shape, move, and disappear or reappear over time,” according to a board-certified dermatologist. Kristina CollinsMD, 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 like antibiotics or NSAIDs, insect bites, and environmental factors like pollen or pet dander,” says Dr. Collins. When hives are caused by an allergic reaction, it may be accompanied by a host of other symptoms, such as shortness of breath, dizziness, difficulty breathing, facial swelling, 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 skin rash. However, not all rashes are hives. “Rashes occur as a result of a compromised skin barrier, drug reactions, viral illness, contact dermatitis and many others,” says a board-certified dermatologist. Mara Weinstein VélezMD, FAAD. “The rashes usually look scaly and ‘angry’ on the skin and have a red or pink color. Many are itchy, but some may also have a burning sensation.”

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

Dr. Collins says a rash refers to 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 health problems. underlying conditions such as eczema or psoriasis. Medications, heat, and friction can also trigger rashes.

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 and reappear on another part of your body. They often leave no lasting skin changes once they disappear.

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

Depending on the cause and source of a rash, it may appear in specific places on your body. “For example, a hairstylist may develop a rash on their hands from touching hair dye all day, which is considered a contact dermatitis-type rash, so it is limited to the hands,” says Dr. Weinstein Velez. “If you ingest a medication that you are allergic to, the rash usually appears all over the body because it was ingested and spread into the bloodstream.”

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

Treatments for hives

When treating hives, the focus is usually on reducing the symptoms and addressing 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. “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. Likewise, corticosteroids treat the same conditions and reduce skin inflammation.

Medications like Benadryl and Zyrtec help speed up the resolution of hives and also help relieve itching. While these can certainly help with hives, avoiding the triggers that cause them is key to prevention. “In cases where an allergen is known, patients may need to carry an epinephrine injector (EpiPen) in case of emergency,” says Dr. Collins.

Treatments for Rashes

Treatment options for rashes are tailored to the cause and source of the rash. You may have a rash due to an allergic reaction or an irritant. Usually, topical treatments are used to 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,” says Dr. Collins. “Moisturizers and emollients are often used to soothe dry, irritated skin.”

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

When to see a doctor

If you’re suffering from a rash or hives, trying an over-the-counter option, like a topical or oral antihistamine, can help soothe your skin and alleviate the problem.

If you have difficulty treating it yourself, you can contact your dermatologist or healthcare professional. They will be able to provide you with a proper diagnosis and an effective treatment plan which may include a prescription biologic or corticosteroids.

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