Fever Rash

A fever rash is a change that can affect your skin’s color, texture or both. Fever and rash are separate symptoms, but both can come from the same source and happen at the same time. Common illnesses, especially infectious diseases, are a common cause. But these symptoms can also signal serious or even dangerous conditions.

Dozens of diseases and conditions can cause a fever and a rash. Experts often call fever-related rashes “febrile” rashes. The features of the rash can be important clues to help medical professionals narrow down the cause. The affected area is called a lesion.

Some of the key features providers look at lesions for include:

• If the rash is one solid lesion or several similar lesions
• If any lesion areas are flat on your skin
• The size of the lesion areas
• If the lesions have fluid inside
• Lesion color
• Rash location
• If the rash is localized around one place or affects larger areas or multiple body parts
• If the rash spreads or changes in any way

Some examples of different forms of febrile rashes can include:

• Macules: Flat lesions
• Papules: Raised lesions that are less than 5 millimeters (mm) across
• Plaques: Raised lesions with a flat surface (like a plateau), and bigger than 5 mm across
• Wheals: Like papules or plaques, but usually pale or tinged pink or red, and sometimes with a ring-like shape when they get bigger
• Vesicles: Fluid-filled bumps that are smaller than 5 mm across
• Bullae: Fluid-filled bumps bigger than 5 mm across
• Pustules: Papules with pus inside (like a pimple)
• Nonpalpable purpura: A spot or patch from bleeding under your skin that you can’t feel with your hand or fingers (those under 3 mm across are petechiae, and those bigger than 3 mm across are ecchymoses)
• Palpable purpura: A lesion from bleeding under your skin that you can feel with your hand or fingers
• Erythema: The medical term for skin redness
• Ulcers: Wounds (in this case, those that are part of or at the center of the rash)
• Eschar: A black, scablike covering on a lesion
• Blanching: That’s when a lesion turns white or pale when you press on it

One reason there are so many potential forms a rash can take is that many conditions can cause both fever and rash.

What are the most common causes of fever rash?

A fever and a rash can happen for dozens of reasons. The causes fall into a few main categories:

• Infectious diseases
• Inflammatory and autoimmune causes
• Cancers and immune suppression causes
• Medications

Infectious diseases

Infectious diseases are some of the most common culprits behind the fever-rash symptom combination. Some examples include:

• Common viral conditions like Epstein-Barr virus (which causes mono), influenza B viruses, herpes type 1, shingles and COVID-19
• Childhood diseases like parvovirus, measles, rubella, roseola, cytomegalovirus (CMV), chickenpox, and hand, foot and mouth disease
• Common bacterial conditions like impetigo (from staph and strep infections), scarlet fever (from Group A strep infections) and scalded skin syndrome
• Mosquito- and insect-carried conditions like dengue fever, trypanosomiasis (from African tsetse flies), West Nile virus, Zika virus and Chikungunya virus
• Tick-borne diseases like Lyme disease, Rocky Mountain spotted fever, ehrlichiosis and Rickettsia-type spotted fevers
• Fungal infections like candidiasis or histoplasmosis
• Sexually transmitted infections like herpes type 2 and syphilis
• Life-threatening conditions like endocarditis, meningococcal infections, toxic epidermal necrolysis and Stevens-Johnson syndrome
• Viral hemorrhagic fevers like Ebola virus disease and the hemorrhagic form of dengue fever

Inflammatory and autoimmune causes

Inflammation can cause both a fever and a rash. So, diseases that cause inflammation, including autoimmune diseases, can cause both symptoms.

Some examples of inflammatory and autoimmune causes of fever and rash include:

• Kawasaki disease
• Lupus
• Still’s disease
• Rheumatic fever

Cancer-related and immune suppression causes

Cancers and diseases that weaken your immune system can often cause fever and rash. Some examples include:

• Sweet syndrome
• HIV (because the virus weakens your immune system, which is what causes AIDS)
• Cancers, including metastatic cancers, and drugs that treat cancer (like chemotherapy)

Medications

Many medications can cause a fever and rash. Experts sometimes refer to this type of reaction as “drug fever.” You should tell your healthcare provider immediately if you get a fever and a rash after taking a medication, especially a new one.

How is fever rash treated?

In general, treating the underlying condition is often the best approach. But that isn’t always possible. Sometimes, the only option is to treat the fever, rash or some of their effects. Some of the possible treatments include:

• Fever-reducing medicines: Drugs like acetaminophen, ibuprofen or aspirin (except for children) are common for lowering fevers.
• Topical medicines: These include medicines you put on your skin that reduce inflammation. Examples include hydrocortisone cream, numbing medicines like lidocaine, and infection treatments like antibacterial ointments.
• Cooling treatments: High fevers can be dangerous or even deadly, so sometimes it takes more aggressive cooling treatments to help. Examples include using cold packs or immersing someone in cool water.
• Bandages and dressings: Open wounds can let germs in. Covering wounds after you clean them can prevent that until your skin heals enough to keep germs out.
• Wound care procedures: Sometimes, wounds need more direct care. Examples include draining pockets of fluid, debriding dead or dying tissue, and more.

What are the possible complications or risks of not treating fever rash?

The complications of not treating fever and rash depend on the underlying cause and your health history. Your healthcare provider can tell you more about complications and what to expect.

When should fever and a rash be treated by a doctor or healthcare provider?

Some conditions that cause fever and rash can be dangerous or even life-threatening. You should get medical care if you have any symptoms of any of the following:

• Meningococcal disease: Light sensitivity, neck stiffness, severe headache
• Toxic epidermal necrolysis or Stevens-Johnson syndrome: Redness that appears over a short time or suddenly, and mainly affects your palms and soles of your feet
• Lyme disease: A bullseye-like rash, especially centered around a tick bite
• Sepsis: Confusion, fatigue, fever, chills, fast heart rate or breathing, or severe pain

Other red flag symptoms or risk factors include:

• Fever of 103 degrees Fahrenheit (39.4 degrees Celsius) or higher
• If the rash involves blisters or wounds on your face or head
• If the fever and rash happen after (within hours, days or even weeks) a bite from an insect, tick, or some kind of animal
• Recent travel, especially out of the country
• Lesions or skin changes across multiple body parts, ranging from just two or three lesions to hundreds
• A wound that may be infected, especially if it has a foul-smelling discharge or it has surrounding, spreading swelling, redness or warmth

In general, it’s better to act out of caution instead of waiting too long. If you think your symptoms might be something more serious, call your healthcare provider or seek medical care. And when in doubt, get emergency care at a hospital, or call 911 (or your local emergency services number).