What is causing my rash? 71 possible causes

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A rash is defined as a widespread eruption of skin lesions. It is a very broad medical term. Rashes can vary widely in appearance. Their causes range from insect bites to HIV and reactions to medications.
A rash can affect one part of the body or cover a large area. Rashes can also be dry, moist, bumpy, smooth, cracked, or blistered. They can involve pain, itching, and color changes.
Some rashes will clear up on their own, some respond to home remedies, but others might be a sign of something more serious that needs medical attention.
Rashes can happen for many reasons, including skin infections, allergies, and medications. They can also result from bacterial, fungal, viral, or parasitic infections and other diseases.
skin infections
allergies
infections
In this article, learn about 71 possible causes of a rash and see images showing how they might appear.
Allergic or sensitivity reactions
Allergies and sensitivities to food and other substances can cause skin rashes.
One of the most common causes of rashes — contact dermatitis — occurs when the skin has a reaction to something that it has touched. The skin may become inflamed, and the rash tends to be weepy and oozy.
contact dermatitis
Common causes include:
dyes in clothes
beauty products
poisonous plants, such as poison ivy and sumac
chemicals, such as latex or rubber
A food allergy can also cause a rash and other symptoms.
food allergy
Hives (urticaria) is a type of rash that often occurs with an allergic or sensitivity reaction. Pruritis is an itchy rash. Hives appear as raised bumps, but on lighter skin, they may also be pink or reddish.
Hives
Pruritis
Learn how hives can appear on dark skin tones.
Learn how hives can appear on dark skin tones.
An allergy can also cause swelling, breathing problems, and other symptoms. This may be a sign of anaphylaxis, a severe allergic reaction that needs urgent medical attention. It can be life threatening.
Anaphylaxis is a severe allergic reaction that can be life threatening. The symptoms develop suddenly and include:
hives
swelling of the face or mouth
wheezing
fast, shallow breathing
a fast heart rate
clammy skin
anxiety or confusion
dizziness
vomiting
blue or white lips
fainting or loss of consciousness
If someone has these symptoms:
Check whether they are carrying an epinephrine pen. If they are, follow the instructions on the side of the pen to use it.
Dial 911 or the number of the nearest emergency department.
Lay the person down from a standing position. If they have vomited, turn them onto their side.
Stay with them until the emergency services arrive.
Some people may need more than one epinephrine injection. If the symptoms do not improve in 5–15 minutes, or they come back, use a second pen if the person has one.
The following slides show pictures of rashes due to contact dermatitis, a hay fever rash, and other allergic and sensitivity reactions. To see all the pictures on one screen, click “view all.”
hay fever
Medications
Certain medications can cause rashes in some people, either as a side effect or an allergic reaction.
can cause rashes
Some medications, including certain antibiotics, can also cause photophobia or photosensitivity. This means they make the individual more susceptible to sunlight. The photosensitivity reaction looks similar to a sunburn.
photophobia
In an allergic reaction, a person’s immune system mistakenly attacks the medication as if it were a pathogen. Symptoms vary depending on the individual and the drug but can include:
a rash, including hives
itchy skin or eyes
swelling
Anyone who experiences a drug reaction should contact their doctor. They may need to change the dose or the drug.
If a person has severe symptoms or finds it difficult to breathe, they should call 911 immediately or go straight to the emergency room.
Learn about the common side effects of antibiotics.
Learn about the common side effects of antibiotics.
The images in the slideshow below show some ways medications, vaccines, and allergy testing might affect the skin.
Bacterial, viral, fungal, and parasitic infections
Infections that involve bacteria, viruses, fungi, or parasites can also cause a rash. These rashes will vary depending on the type of infection. For instance, candidiasis, a common fungal infection, causes an itchy rash that generally appears in skin folds.
candidiasis
fungal infection
Anyone who believes they may have an infection should seek medical advice.
The slides below include pictures of 29 types of bacterial, fungal, parasitic, and viral rashes.
viral rashes
These rashes can appear with:
fifth disease (erythema infectiosum)
fifth disease (erythema infectiosum)
impetigo
impetigo
shingles
shingles
scarlet fever
scarlet fever
rheumatic fever
rheumatic fever
mononucleosis (“mono”)
mononucleosis (“mono”)
measles
measles
candidiasis, a yeast infection
candidiasis
yeast infection
ringworm
ringworm
rubella
rubella
meningitis
meningitis
sepsis and septic shock
sepsis
septic shock
cellulitis
cellulitis
methicillin-resistant Staphylococcus aureus (MRSA)
methicillin-resistant Staphylococcus aureus (MRSA)
chickenpox
chickenpox
toxic shock syndrome
toxic shock syndrome
hand, foot, and mouth
hand, foot, and mouth
syphilis
syphilis
COVID-19, symptoms of which can include “COVID toes“
COVID-19
COVID toes
Mycoplasma pneumoniae, a type of bacterial pneumonia
Mycoplasma pneumoniae
bacterial pneumonia
erysipelas
erysipelas
histoplasmosis
histoplasmosis
lymphangitis
lymphangitis
HIV rash, which can be an early sign of HIV
HIV rash
HIV
acrodermatitis, which can happen with late-stage Lyme disease
Lyme disease
West Nile virus
West Nile virus
dengue fever
dengue fever
hookworm
hookworm
scabies
scabies
To see all the pictures, click “view all.”
Gallery was here
Autoimmune diseases
An autoimmune disease occurs when an individual’s immune system begins to attack healthy tissue. There are many autoimmune diseases. They can cause symptoms throughout the body, including rashes.
autoimmune disease
can cause
In the following slides, find examples of rashes and skin changes that can occur with:
a type of eczema known as atopic dermatitis
eczema
atopic dermatitis
sarcoidosis
sarcoidosis
plaque psoriasis
plaque psoriasis
inverse psoriasis
inverse psoriasis
erythrodermic psoriasis
erythrodermic psoriasis
guttate psoriasis
guttate psoriasis
psoriatic arthritis
psoriatic arthritis
systemic lupus erythematosus, also known as lupus
systemic lupus erythematosus
lupus
bullous pemphigoid
bullous pemphigoid
adult-onset Still’s disease
adult-onset Still’s disease
Learn more
Some skin conditions can appear differently on darker skin tones, making misdiagnosis more likely.
How can psoriasis appear on darker skin?
How can psoriasis appear on darker skin?
How can eczema appear on darker skin?
How can eczema appear on darker skin?
What does a lupus rash look like on darker skin?
What does a lupus rash look like on darker skin?
How can ringworm, shingles, and other rashes appear on darker skin?
How can ringworm, shingles, and other rashes appear on darker skin?
Bites, stings, and outdoor rashes
Many insects can cause a rash through a bite or sting. Although the reaction will vary depending on the person and the animal, symptoms often include:
a rash
redness, purple, or darkening of the skin, depending on the skin tone
itching
itching
pain
swelling at the site of the bite or sting
more widespread swelling
Other causes of rashes outdoors include hay fever (seasonal allergy) and exposure to poison ivy and other plants. If a person has a skin reaction to pollen, poison ivy, a jellyfish sting, brown-tail moth caterpillars, and other plants or animals, a doctor may refer to it as contact dermatitis.
The images below show how a skin reaction or rash may affect people after exposure to:
wasp sting
wasp sting
fleabites
fleabites
poison ivy
poison ivy
a brown-tail moth caterpillar
stinging nettles or jellyfish
stinging nettles
jellyfish
grass
grass
Learn the difference between fleabites and bed bug bites.
Learn the difference between fleabites and bed bug bites.
Read about bee sting allergies.
Read about bee sting allergies.
Cosmetics, cleaning products, and other household exposures
Chemical burns can occur when a person comes in direct contact with a chemical or its fumes, including some household products. Symptoms vary but can include:
skin that appears black or dead
irritation or burning in the affected area
redness or a darkening of the skin, depending on the skin tone
numbness and pain
Inhaling the fumes could lead to swelling of the throat, lips, and tongue and difficulty breathing.
Some people have a reaction to the perfumes or chemicals in soaps, shampoos, and other products. A doctor may class these types of reactions as contact dermatitis.
The images below show how various exposures can affect the skin.
A range of other health conditions can involve a rash or skin reaction. They include circulatory problems, hormonal conditions, and others.
The pictures below show examples of rashes due to:
Stasis dermatitis
Stasis dermatitis
Addison’s disease
Addison’s disease
dermatitis neglecta
dermatitis neglecta
dermatomyositis
dermatomyositis
panniculitis, a complication of gout
panniculitis
gout
ichthyosis vulgaris
ichthyosis vulgaris
porphyria
porphyria
Kawasaki disease
Kawasaki disease
Home remedies
Rashes come in many forms and develop for many reasons.
However, some basic measures can speed up recovery and ease some of the discomfort:
Use mild soap, baby soap, or soap for sensitive skin. Avoid scented soaps.
mild soap
Wash in warm water, not hot water.
Wear loose-fitting cotton clothes.
Ask a doctor or pharmacist about using moisturizers and emollients.
Do not cover a rash with a Band-Aid or bandage.
Do not rub the rash dry. Instead, pat it.
For a dry rash, for instance, in eczema, use unscented moisturizers.
eczema
unscented moisturizers
Avoid any cosmetics or lotions that may be causing the rash, for instance, newly purchased items.
Avoid scratching, as scratching increases the risk of infection.
Ask a pharmacist about over-the-counter cortisone creams to ease itching.
Calamine can relieve some rashes, such as poison ivy, chickenpox, and poison oak.
chickenpox
For rashes due to chronic diseases, such as psoriasis, managing stress may help reduce symptoms.
may help reduce
If a rash causes pain, acetaminophen or ibuprofen may be useful. These can help manage symptoms but will not treat the cause of the rash.
ibuprofen
It is important to speak with a doctor before taking any medication. Compare brands before purchasing over-the-counter or online products, to ensure the product is suitable.
Learn some natural and home remedies for itching.
Learn some natural and home remedies for itching.
Seeing a doctor
If a rash occurs with the following features, a person should seek medical advice:
a sore throat
sore throat
pain in joints
a recent animal or insect bite
red, purple, or dark streaks near the rash
tender regions near the rash
a large collection of pus
pus
Most rashes are not a major cause for concern, but anyone with the following symptoms should seek emergency medical care:
quickly changing coloration on the skin
difficulty breathing or feeling like the throat is closing up
difficulty breathing
increasing pain or severe pain
high fever
fever
confusion
dizziness
swelling of the face or extremities
swelling
severe pain in the neck or head
repeated vomiting or diarrhea
diarrhea
Rashes can appear differently depending on a person’s skin tone, which can affect diagnosis. Here, find out how various rashes may appear in different skin colors.
Here
Frequently asked questions
Here are some frequently asked questions about skin rashes.
A person may be able to identify the cause of their rash based on the location of the rash or other symptoms they may experience. For example, swelling and breathing problems might indicate an allergy, while a fungal infection such as candidiasis can cause a rash in the skin folds. Factors such as whether the rash is flat or raised, peeling, or painful can help determine the type of rash.
However, it is best to contact a doctor for an accurate diagnosis if a person develops a rash.
There are many different types of rash. Examples of possible causes include:
allergic reaction
reaction to an insect bite or sting
sensitivity to cosmetics, cleaning products, or other chemicals or irritants
side effects of medication
bacterial, viral, fungal, and parasitic infection
autoimmune diseases
Treatment for the rash can depend on the cause. A person’s doctor can provide an accurate diagnosis and advise on ways to manage symptoms.
Summary
Rashes can happen for many reasons. Some are mild and need no intervention, while others can be a sign of a severe underlying disorder.
Knowing how to recognize skin changes can help a person access early treatment for conditions that could otherwise lead to severe complications.