A rash is an area of irritated or swollen skin. Rashes on skin may be red, itchy, or painful and can involve blisters, bumps, or raw skin.
Rashes can be a response to an allergen, irritant, infection, or systemic disease. They range from minor tissue swelling to an outbreak of painful sores.
Some rashes on skin affect a small area while others are widespread. They’re sometimes tough to tell apart—even for a trained eye.
Broadly speaking, rashes on skin can be classified as either infectious or non-infectious. Many types and possible causes exist.
This article will help you learn to identify 13 common rashes, including impetigo, athlete's foot, psoriasis, shingles, and more.
Impetigo
Impetigo is a common skin infection. It's usually caused by either Streptococcus (strep) or Staphylococcus (staph) bacteria.
Impetigo is most common on the face or limbs. Its distinctive features are:
- An eruption of red sores
- Clear fluid or pus leak from sores
- Formation of a honey-colored crust
Bacteria typically enter your body through a cut, scrape, burn, or insect bite.
Children often get impetigo after a cold. Using tissues makes the skin around their noses raw. And that gives the bacteria easy access.
The honey-colored crust is usually a tell-tale sign of impetigo. Still, your healthcare provider may order a bacterial culture to confirm the diagnosis.
When impetigo involves large blisters (known as bullae), it’s called bullous impetigo. It’s a less common form. Young children are most likely to have it.
Impetigo may cause minor itchiness. But it’s generally not painful. That sets it apart from shingles and other types of eruptive lesions.
Impetigo is typically treated with antibiotics.
Athlete’s Foot (Tinea Pedis)
Athlete’s foot (tinea pedis) is a common fungal infection. Symptoms include:
- A red rash between the toes or on the soles of the feet
- Flaking or broken skin
- Discomfort ranging from mild itchiness to painful blisters
Athlete’s foot between the toes is called interdigital tinea pedis. When it’s mainly on the soles, it’s moccasin-type tinea pedis. Blister-like outbreaks are acute vesicular tinea pedis. (Vesicle means blister.)
Athlete’s foot spreads easily in moist, unhygienic environments. That can include spas and locker room floors. It’s treated with topical antifungals.
Healthcare providers often diagnose athlete’s foot on appearance alone. However, other conditions, like plaque psoriasis, can cause similar symptoms, so if your rash doesn’t respond to antifungals, you may be tested for other causes.
Psoriasis
Psoriasis is an autoimmune skin disorder. It’s chronic and inflammatory. Triggers may include:
- Stress
- Medications
- Infection
- Skin injury
- Environmental triggers like the sun
About 2% of the global population has psoriasis.
In autoimmune disorders, your immune system mistakenly attacks healthy tissues. This triggers inflammation.
In psoriasis, the skin cells are attacked. New ones are produced faster than the old ones can be shed. That leads to a buildup of cells—the psoriasis rash.
Plaque psoriasis is the most common form of psoriasis. Symptoms include:
- Red or dark patches of skin covered with thick, silvery scales
- Itching, burning, and/or soreness
- Flaking, cracked, dry skin that can bleed when scratched
Plaque psoriasis is most common on the elbows, knees, and scalp.
Other types of psoriasis are:
- Pustular psoriasis: Pus-filled lesions
- Guttate psoriasis: Small, pink bumps shaped like teardrops
Psoriasis is often diagnosed by its appearance. It may require a skin biopsy for confirmation.
No blood tests can diagnose psoriasis. Your healthcare provider may rule out similar skin conditions such as:
Treatment varies by the severity of the outbreak. It may include topical steroids, immunosuppressants, and UV light therapy.
Psoriasis sometimes goes away without treatment. It can recur suddenly, as well.
Shingles
Shingles (herpes zoster) is a painful rash. It’s caused by a reactivation of the varicella virus. That’s the virus that causes chickenpox.
Most people have a 30% chance of developing shingles at some point during their lifetime. High-risk groups include people with compromised immune systems.
Shingles typically strikes later in life. Symptoms often come in two phases:
- Pre-eruptive stage: A dull, localized ache and increased sensitivity to touch.
- Eruptive stage: Tiny, painful blisters appear. They may burst and scab over.
Shingles is contagious during the blistering phase.
Shingles almost always affects just one side of the body. It’s a nerve infection and is limited to an area of skin supplied by a single nerve. This area is called a dermatome.
The pain of shingles ranges from prickly, persistent discomfort to deep, excruciating pain.
Shingles sometimes causes long-term nerve pain. This is called postherpetic neuralgia. Older adults and those whose shingles is untreated are at higher risk.
See a healthcare provider as soon as you recognize the rash with fluid-filled blisters. Early treatment with antiviral drugs such as Zovirax (acyclovir) can shorten the outbreak. It also keeps it from spreading to vulnerable parts, like your eyes.
A highly effective shingles vaccine known as Shingrix (recombinant zoster vaccine) is available. Vaccination is recommended for all adults 50 and older.
Ringworm (Tinea Corporis)
Ringworm (tinea corporis) is a common fungal infection that, despite its name, is in no way related to worms. Symptoms of ringworm may include:
- Round rash with raised, red edges
- Flaking and peeling
- Itchiness
- Skin cracking
- Hair loss in the affected area
Ringworm is not inherently painful. It can appear anywhere on the body but is mostly seen on the trunk, arms, and legs.
Tinea capitis is a related fungal infection that involves the scalp.
Ringworm is highly contagious and easily spread through skin-to-skin contact with a lesion. It can also be passed through contaminated surfaces or everyday objects such as clothing, towels, and bedding.
Ringworm is typically diagnosed based on its appearance.
It is important to note that other rashes can also present with ring-shaped lesions, including pityriasis rosea and granuloma annulare or those associated with sarcoidosis and lupus.
Once diagnosed, ringworm can be effectively treated with oral or topical antifungal medications.
Scabies
Scabies is a contagious skin condition caused by a tiny mite that burrows its way beneath the skin. Like head lice, it can spread quickly through schools and nursing homes and is easily passed between family members.
Symptoms of scabies include:
- Rash that causes tiny bumps, often in a linear track-like pattern
- Itching, often severe (particularly at night)
- Skin crusting (most commonly associated with crusted scabies)
- Bleeding and sores due to scratching
Scabies most often develops on the wrists, elbow, buttocks, waist, armpits, genitalia, and between the fingers.
Scabies can mimic other skin conditions, such as folliculitis. To make a definitive diagnosis, a doctor will need to scrape the affected skin and examine it under a microscope for evidence of infestation.
The treatment of scabies involves the use of 5% permethrin cream or lotion, often in tandem with oral antihistamines or topical steroids to treat the rash.
Eczema
Eczema, also known as atopic dermatitis, is an inflammatory skin condition that can affect people of all ages but occurs more frequently in children.
The most common symptoms of eczema are:
- A red, itchy rash
- Dry, rough, or scaly skin
- Small, fluid-filled blisters
- Cracked or broken areas of skin
- Oozing, weeping, or crusting
Although the exact cause of eczema is unknown, it’s believed to be the result of genetic and environmental factors. Doctors can diagnose eczema based on its physical appearance and whether the symptoms meet specific diagnostic criteria.
The diagnosis of eczema typically requires the exclusion of all other possible causes. Other tests, such as a patch test, may be ordered to rule out skin conditions like contact dermatitis.
There is no cure for eczema, but there are treatments that can help manage it. Mild eczema can often be controlled with emollient-rich moisturizers and over-the-counter hydrocortisone creams. Moderate to severe cases may require prescription drugs.
Eczema can be difficult to manage, so many patients find the need to try different treatment options or even change their treatment regimen over time.
Hives (Urticaria)
There are times when an allergy or infection will cause the immune system to release a substance called histamine into the bloodstream. When this happens, tiny blood vessels in the skin expand and leak fluid into the outermost layer, called the epidermis. This results in raised, red bumps or welts, a skin condition recognized as hives (urticaria).
Hives are transient. They typically last for less than 24 hours and often go away within minutes or hours, but may appear in new areas as well.
Hives may:
- Look spongy or like bug bites
- Appear as red, raised areas of inflammation with no distinct border
- Whiten (blanch) when you press them
- Affect large areas of skin
- Be intensely itchy
Angioedema, may also be present. It is a closely related condition in which swelling occurs in deeper tissue layers (typically around the eyes, lips, and face).
Hives can also develop in response to hot or cold temperatures, excessive perspiration, and stress. While hives will usually go away on their own, antihistamines may be used to relieve itching and inflammation.
Pityriasis Rosea
Pityriasis rosea is a common, benign rash that often starts as a single large spot (called a “herald patch”) on the chest, abdomen, or back. This is soon followed by the appearance of other smaller patches or bumps, often in a pine tree-like pattern.
A pityriasis rosea rash is typically red, scaly, and sometimes itchy. It often has a ring-like appearance similar to ringworm in the early stages. Those affected often feel unwell for a day or two prior to the onset of skin symptoms.
Pityriasis is also commonly seen on the upper arms and upper legs but rarely on the face (except in children). Pityriasis can progress over the course of days or weeks.
Pityriasis rosea is not well understood but is believed to be caused by a virus. There are no tests to diagnose the condition, so a doctor must rely on a physical exam. That said, if the symptoms are severe, tests may be performed to rule out other causes, including guttate psoriasis, lichen planus, and nummular eczema.
While treatment is typically not indicated for pityriasis rosea, a topical steroid or antihistamine may be used if the rash is especially itchy.
Herpes Simplex
Herpes simplex is a viral infection caused by either herpes simplex virus type 1 (HSV-1), the type commonly associated with cold sores, or herpes simplex type 2 (HSV-2), the type most commonly linked to genital herpes.
Herpes is characterized by the formation of open and sometimes painful ulcers. An outbreak initially presents with tingling and redness that later progresses to the formation of blistering lesions. The lesions can sometimes merge into larger open, weeping sores.
A herpes outbreak can be painful and sometimes severe. Fever and swollen lymph nodes may accompany or precede the onset of skin symptoms.
Herpes can be transmitted through contact with a sore or bodily fluids from an infected individual. Transmission can even occur when there are no visible lesions.
Once infected, you can experience a relapse of symptoms at any time (although the first outbreak tends to be the worst). While cold sores and genital herpes may be diagnosed by appearance alone, it is possible for HSV-2 to cause a cold sore if transmitted through oral sex. Similarly, HSV-1 can cause genital lesions.
Herpes simplex can be differentiated from herpes zoster based on the area the lesions appear on the body. Primary syphilis and chancroid can also be distinguished from HSV, as they usually only cause single sores. If there is any doubt as to the cause of the sore, a simple test called polymerase chain reaction (PCR) can be used to confirm the presence of viral DNA.
Herpes simplex can be treated with antiviral drugs such as Zovirax (acyclovir) or Valtrex (valacyclovir). There are currently no vaccines that protect against herpes simplex.
Contact Dermatitis
Contact dermatitis is a rash that develops when you come in contact with something that irritates your skin or causes an allergic reaction.
Common irritants include acids, alkaline materials (such as soaps and detergents), solvents, or other chemicals. They can cause a reaction just after a short period of contact.
However, it can take 24 to 48 hours after exposure for an allergic reaction to occur. Common allergens include:
- Fragrances
- Nickel or other metals
- Rubber or latex
- Poison ivy or poison oak
Contact dermatitis only occurs on areas of skin that have touched an irritant or allergen. Symptoms of this rash include:
- Red bumps
- Itchiness
- Small, fluid-filled blisters
- Oozing, weeping, or crusting
- Scaly, raw, or thickened skin
This type of rash is self-limiting and usually goes away on its own once the triggering substance is removed and/or avoided. Topical steroids may be used for symptom relief. Severe cases may require additional treatment.
Rosacea
Rosacea is a chronic inflammatory skin condition characterized by a red rash—usually on the nose and cheeks. It is thought to be caused by genetic and environmental factors.
Symptoms of rosacea may include:
- Red, sensitive skin
- Flushing
- Red bumps
- Pus-filled bumps
- Tiny visible blood vessels near the surface of the skin
- Eye irritation
There is no cure for rosacea. Managing this skin condition typically involves avoiding triggers that worsen symptoms and adopting a special skincare routine.
Measles
Measles is a contagious illness caused by a viral infection. It causes a blotchy red rash that often starts on the face and moves down to the body. Small raised bumps may also be present.
This rash is often preceded by other symptoms such as:
- Fever
- Cough
- Runny nose
- Watery eyes
- Pink eye (conjunctivitis)
- Tiny white spots inside the mouth (Koplik's spots)
Measles typically resolves on its own within one week after the onset of rash. In some cases, serious complications can occur. That said, this illness can be especially dangerous for babies and young children.
There is no specific treatment for measles. However, the MMR vaccine can help prevent it.
When to Call Your Healthcare Provider
While most skin rashes are not life-threatening, a rash can sometimes mean something more serious is happening in your body.
If you have a rash and notice any of the following symptoms, you should contact your healthcare provider for an evaluation:
- The rash hurts.
- The rash comes and goes.
- The rash is made up of blisters or open sores, or the sores affect the skin around your eyes, mouth, or genitals.
- The rash prevents you from getting sleep or interferes with your daily activities.
In some cases, a rash can be a sign of a life-threatening condition. Should you notice any of the following, call 911 or go to the emergency room:
- The rash is all over your body or is spreading rapidly. This could mean you are having an allergic reaction.
- The rash is painful, oozing pus, swollen, warm to the touch, or there is a red streak coming from the rash. These are signs that the rash is infected.
- The rash is accompanied by a fever, which could mean you have an infection. It can also be a sign of a disease such as herpes, measles, shingles, or mononucleosis.
- The rash is accompanied by dizziness, difficulty breathing, vomiting, a stiff neck, or any other unusual or worrisome symptoms.
How Long Should You Have a Rash Before Going to the Doctor?
If your rash is recurring or does not go away within a week of it developing, schedule an appointment with your healthcare provider. You may need a stronger treatment for your rash, or you may have an underlying condition that needs to be diagnosed.
Summary
Rashes are irritated skin. They can be caused by many different things. They each have distinguishing features.
If you develop a rash and don’t know what it’s from, get medical attention. The rash itself may not be harmful. But it could be a symptom of a condition that needs to be treated.