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.
Illustration by Zoe Hansen for Verywell Health
Theyre sometimes tough to tell aparteven for a trained eye.
Broadly speaking, rashes on skin can be classified as either infectious or non-infectious.
Manytypesand possible causes exist.
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Impetigo
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Impetigois a common skin infection.
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It’s usually brought on by eitherStreptococcus(strep) orStaphylococcus(staph) bacteria.
Impetigo is most common on the face or limbs.
Children often get impetigo after a cold.
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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.
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Still, your healthcare provider may order a bacterial culture to confirm the diagnosis.
When impetigo involves largeblisters(known as bullae), its called bullous impetigo.
Its a less common form.
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Young children are most likely to have it.
Impetigo may cause minor itchiness.
But its generally not painful.
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That sets it apart from shingles and other types of eruptive lesions.
Impetigo is typically treated with antibiotics.
Athletes Foot (Tinea Pedis)
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Athletes foot(tinea pedis)is a common fungal infection.
Symptoms include:
Athletes foot between the toes is calledinterdigitaltinea pedis.
When its mainly on the soles, its moccasin-key in tinea pedis.
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Blister-like outbreaks are acute vesicular tinea pedis.
Athletes foot spreads easily in moist, unhygienic environments.
That can include spas and locker room floors.
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Its treated withtopical antifungals.
Healthcare providers often diagnose athletes foot on appearance alone.
Psoriasis
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Its chronic and inflammatory.
Triggers may include:
About 2% of the global population has psoriasis.
In autoimmune disorders, your immune system mistakenly attacks healthy tissues.
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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 cellsthe psoriasis rash.
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Plaque psoriasis is the most common form of psoriasis.
Symptoms include:
Plaque psoriasis is most common on the elbows, knees, and scalp.
Other types of psoriasis are:
Psoriasis is often diagnosed by its appearance.
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It may require a skin biopsy for confirmation.
No blood tests can diagnose psoriasis.
It may include topical steroids,immunosuppressants, andUV light therapy.
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Psoriasis sometimes goes away without treatment.
It can recur suddenly, as well.
Shingles
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Shingles (herpes zoster)is a painful rash.
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Its due to a reactivation of the varicella virus.
Thats the virus that causes chickenpox.
Most people have a 30% chance of developing shingles at some point during their lifetime.
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High-risk groups include people with compromised immune systems.
Shingles typically strikes later in life.
Symptoms often come in two phases:
Shingles is contagious during the blistering phase.
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Shingles almost always affects just one side of the body.
Its a nerve infection and is limited to an area of skin supplied by a single nerve.
This area is called adermatome.
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The pain of shingles ranges from prickly, persistent discomfort to deep, excruciating pain.
Shingles sometimes causes long-term nerve pain.
This is calledpostherpetic neuralgia.
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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 treatmentwithantiviral drugssuch as Zovirax (acyclovir) can shorten the outbreak.
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It also keeps it from spreading to vulnerable parts, like your eyes.
A highly effectiveshingles vaccineknown as Shingrix (recombinant zoster vaccine) is available.
Vaccination is recommended for all adults 50 and older.
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Ringworm (Tinea Corporis)
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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.
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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.
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Once diagnosed, ringworm can be effectively treated with oral or topical antifungal medications.
Likehead lice, it can spread quickly through schools and nursing homes and is easily passed between family members.
Scabies can mimic other skin conditions, such as folliculitis.
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Eczema
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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.
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Other tests, such as apatch test, may be ordered to rule out skin conditions likecontact 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-counterhydrocortisone creams.
Moderate to severe cases may require prescription drugs.
Hives (Urticaria)
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This results in raised, red bumps or welts, a skin condition recognized as hives (urticaria).
Hives may:
Angioedema, may also be present.
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.
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 can progress over the course of days or weeks.
Herpes Simplex
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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.
Similarly, HSV-1 can cause genital lesions.
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
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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:
Contact dermatitis only occurs on areas of skin that have touched an irritant or allergen.
Topical steroids may be used for symptom relief.
Severe cases may require additional treatment.
Rosacea
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Rosaceais a chronic inflammatory skin condition characterized by a red rashusually on the nose and cheeks.
It is thought to be sparked by genetic and environmental factors.
Symptoms of rosacea may include:
There is no cure for rosacea.
Managing this skin condition typically involves avoiding triggers that worsen symptoms and adopting a special skincare routine.
Measles
Measlesis a contagious illness resulting from 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.
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, theMMR vaccinecan help prevent it.
Summary
Rashes are irritated skin.
They can be brought on by many different things.
They each have distinguishing features.
If you develop a rash and dont know what its 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.
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