What Is a Viral Skin Rash? Causes, Treatment, and Prevention

Viral skin rashes (also known as viral exanthems) can cause itching, irritation, and pain — and possibly symptoms like fever or fatigue.

Understanding the difference between viral skin rashes is key to effectively treating and preventing symptoms. Here are some of the most common viral rashes, what they look like, and who’s most at risk.

Measles

“The measles rash looks like blotchy red or violet patches that can be flat or raised with a bumpy texture. It can merge as the rash spreads,” says Geeta Yadav, MD, a board-certified dermatologist in Toronto. “Tiny white spots can appear on top of these patches and may also appear in the mouth.”

Rubella

Roseola

Chicken Pox (Varicella Zoster)

Shingles (Herpes Zoster)

Fifth Disease 

The condition starts with symptoms like fever, vomiting, and diarrhea, followed by its characteristic "slapped-cheek" rash — a bright red, raised, and itchy rash on the cheeks, says Yadav. Some people also develop a second rash on the torso or buttocks that has a "lacy” appearance.

Hand, Foot, and Mouth Disease

Molluscum Contagiosum

Molluscum contagiosum (also called water warts) is a viral skin infection caused by a virus of the same name. It’s most common in children, and causes flesh-colored, dome-shaped bumps with a central dimple that can be painful or irritating, says Dr. Goldenberg.

“While the bumps may resolve on their own, it can take approximately one and a half years,” he says.

Herpes Simplex Virus

Identifying viral rashes is crucial if your symptoms call for treatment to prevent complications. It can also help you determine whether to avoid contact with other people. Here’s what several common viral rashes may look like.

1. Measles

2. Rubella

3. Roseola

4. Chicken Pox

5. Shingles

6. Fifth Disease

7. Hand, Foot, and Mouth Disease

8. Molluscum Contagiosum

9. Herpes Simplex Virus

“Viral skin rashes can range from mild to severe,” says Hannah Kopelman, DO, a board-certified dermatologist in New York City. “Some resolve on their own without complications, while others — such as measles or shingles — can be serious.”

Conditions like rubella; roseola; fifth disease; hand, foot, mouth disease; and molluscum contagiosum are generally harmless. Rashes often accompany mild symptoms and tend to clear up on their own at home with over-the-counter (OTC) fever reducers or pain relievers, Dr. Kopelman says.

Certain viral rashes, though, can be severe and may lead to other health issues. These include:

• Measles Left untreated, the measles virus can lead to pneumonia or brain inflammation (encephalitis), which can be life-threatening, says Kopelman. See your doctor as soon as you’ve been exposed to measles; they may be able to give you an antibody treatment (these are made of proteins your immune system creates to fight viruses) that lowers your risk of illlness.

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• Shingles Shingles can cause long-term nerve pain for some, says Yadav, so it’s important to see a doctor as soon as you notice symptoms. Seek medical care immediately if you have a shingles rash near your eye — without proper treatment, this can cause permanent eye damage.

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• Chicken Pox Though most cases of chicken pox resolve on their own, certain symptoms can be cause for concern. See a doctor if there are sores in the eyes, sores with yellow pus, or severe headache or fever.

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• Herpes Prescription medications like pills, creams, and drops can help prevent a herpes rash from flaring up, so it’s important to visit your doctor if you have any symptoms. Some treatments are used long-term to prevent outbreaks, while others are used temporarily to relieve an active flare.

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In general, you should make an appointment with your doctor if your rash is accompanied by a high fever, difficulty breathing, severe pain, or signs of bacterial infection, such as increased redness, swelling, warmth, or pus, says Kopelman.

Seek urgent care if the rash spreads quickly, does not improve, or is accompanied by confusion or difficulty walking, she adds.

It’s possible to diagnose some rashes without any testing.

Other viral rashes may require additional testing for a diagnosis, says Kopelman. Common tests include:

• Blood Test Your blood may contain antibodies (proteins your immune system uses to fight disease) that reveal the underlying condition causing your rash.

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• Polymerase Chain Reaction (PCR) Test Your doctor may swab your blister, nose, or throat to collect a small sample of body fluid, which they can then test for bacteria and viruses. This is known as a PCR test.

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• Skin Biopsy Your doctor may conduct a skin biopsy, which involves cutting off a small piece of your rash to test the skin cells for disease.

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The best treatment for a viral rash ultimately depends on the underlying virus, says Kopelman. “Most viral rashes only require supportive care like hydration, rest, antihistamines, and soothing skin treatments like calamine lotion or oatmeal baths,” she says.

For instance, viral skin rashes (and the underlying virus) from rubella, roseola, molluscum contagiosum, chicken pox, fifth disease, measles, and hand-foot-and-mouth disease typically clear up on their own. (The viruses that cause herpes and shingles stay in the body.) Managing skin discomfort or fever from viral infections may only require OTC pain-relieving medicine like ibuprofen, acetaminophen, or diphenhydramine.

Some patients require extra help to resolve symptoms, says Kopelman. Treatments for viral rashes may include:

• Antiviral Medications Rashes from shingles and herpes may require prescription antiviral drugs to reduce symptoms and shorten the length of flare-ups. For shingles treatment, antiviral medications are temporary and work best when you take them within 72 hours of when symptoms start.

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   Some cases of herpes only require temporary medication to treat flare-ups, but people with genital herpes who experience frequent or severe outbreaks, have a weakened immune system, or have multiple sexual partners may require long-term treatment to stay under control.

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• Antibacterial Drugs Some viral rashes, like the shingles rash, can cause a bacterial infection in your skin.

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   If that’s the case, your doctor can prescribe an antibiotic to fight the infection.

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• Medications Your doctor may prescribe topical creams or oral medication for viral rash symptoms like itching, pain, or swelling. For instance, gabapentin, lidocaine, and antidepressants (such as amitriptyline) may be prescribed to ease shingles pain.

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   Podophyllum, salicylic acid, and tretinoin are topical medications that are commonly used to treat molluscum contagiosum bumps, and are available by prescription and OTC.

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   Treatment is typically temporary, though your doctor will tell you exactly how long to use your medication based on your symptoms.
• Bump Removal If you have molluscum contagiosum, your doctor may recommend removing the bumps via scraping (using a small tool to scrape off), cryotherapy (freezing off the bumps), or laser therapy (using light beams to destroy the bumps).

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Certain viral infections can lead to complications that require medical care. According to Kopelman, potential complications include:

• Bacterial Infection Scratching or scarring can lead to secondary infections that may require prescription antibiotics, says Kopelman. If you notice any redness, swelling, warmth, or pus developing on your rash, you may have a bacterial infection and should visit your doctor.
• Neurological Issues Shingles can lead to lasting nerve damage that causes pain even after the rash is gone. Other potential complications include facial paralysis, difficulty hearing, balance issues, and encephalitis. Visit your doctor as soon as you show symptoms of shingles to minimize your risk for complications.

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• Blindness and Deafness “Measles can be very serious — complications include blindness, deafness,” says Yadav. “For those who have compromised immune systems or have not been vaccinated, it can be lethal.” Visit the doctor as soon as you’re exposed to the virus to prevent these issues.

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• Encephalitis This dangerous form of brain inflammation can occur days to years after a measles infection, so see your doctor as soon as you experience measles symptoms to avoid this complication.

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While preventing viral rashes depends on the specific virus, there are steps you can take to lower your risk of viral skin rashes. According to Kopelman, these include:

• Vaccination Getting vaccinated for conditions that cause viral rashes — like measles, chicken pox, and shingles — is critical for lowering your risk.
• Good Hygiene Frequent handwashing and cleaning of shared surfaces can help reduce the spread of contagious viruses. Good hygiene is also critical for healing skin infections and preventing complications down the line.
• Social Distancing Avoid close contact and skin-to-skin touching, and don’t share personal items (like towels or razors) with infected people to prevent the spread of infections like herpes and molluscum contagiosum.
• Antiviral Medication For viruses like herpes that flare up from time to time, your doctor may recommend antiviral drugs long-term to prevent outbreaks.

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The Takeaway

• Viral conditions like measles, chicken pox, rubella, and more can cause viral skin rashes with itchy, irritated, or painful spots, bumps, or blotches.
• While many viral rashes resolve on their own, some (like shingles) can lead to serious complications if left untreated.
• Seek immediate medical care if your rash spreads, swells, feels warm, or produces yellow pus, or if you experience symptoms like high fever, difficulty breathing, or severe pain.
• Vaccination is the most effective way to prevent viral infections like measles, chicken pox, and shingles.