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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 in appearance greatly, and there are many potential causes. Because of the variety, there is also a wide range of treatments.
A rash can be local to just one small part of the body, or it can cover a large area.
Rashes come in many forms, and common causes include contact dermatitis, bodily infections, and allergic reactions to taking medication. They can be dry, moist, bumpy, smooth, cracked, or blistered; they can be painful, itch, and even change color.
Rashes affect millions of people across the world; some rashes may need no treatment and will clear up on their own, some can be treated at home; others might be a sign of something more serious.
There are a number of potential causes of rashes, including allergies, diseases, reactions, and medications. They can also be caused by bacterial, fungal, viral, or parasitic infections.
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 red and inflamed, and the rash tends to be weepy and oozy. Common causes include:
- dyes in clothes
- beauty products
- poisonous plants, such as poison ivy and sumac
- chemicals, such as latex or rubber
Certain medications can cause rashes in some people; this may be a side effect or an allergic reaction. Also, some medications, including some antibiotics, cause photosensitivity – they make the individual more susceptible to sunlight. The photosensitivity reaction looks similar to sunburn.
Infections by bacteria, viruses, or fungi 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.
It is important to see a doctor if an infection is suspected.
Rashes come in many forms and develop for many reasons.
However, there are some basic measures that can speed up recovery and ease some of the discomfort:
- Use mild soap – not scented. These soaps are sometimes advertised for sensative skin, or for baby skin.
- Avoid washing with hot water – opt for warm.
- Try to allow the rash to breathe. Do not cover with a Band-Aid or bandage.
- Do not rub the rash dry, pat it.
- If the rash is dry, for instance, in eczema, use unscented moisturizers.
- Do not use any cosmetics or lotions that may be causing the rash – for instance, newly purchased items.
- Avoid scratching to lessen the risk of infection.
- Cortisone creams that can be purchased over-the-counter or online may ease itching.
- Calamine can relieve some rashes, e.g. poison ivy, chickenpox, and poison oak.
If the rash causes mild pain, acetaminophen or ibuprofen may be useful, but these are not a long-term solution – they will not treat the cause of the rash.
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.
If a rash occurs with the following symptoms, it is important to visit a doctor:
- a sore throat
- pain in joints
- if you have had a recent animal or insect bite
- red streaks near the rash
- tender regions near the rash
- a large collection of pus
Although the majority of rashes are not a major cause for concern, anyone experiencing the following symptoms should go to the hospital straight away:
1. Bites and stings
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:
- redness and rash
- swelling – either localized to the site of the bite or sting or more widespread
2. Flea bites
Fleas are tiny jumping insects that can live in fabrics within the home. They have a very fast breeding cycle and can take over a home very rapidly.
- flea bites on humans often appear as red spots
- the skin can become irritated and painful
- secondary infections can be caused by scratching
3. Fifth disease
Also known as erythema infectiosum and slapped cheek syndrome, fifth disease is caused by the parvovirus B19. One of the symptoms is a rash, which appears in three stages:
- A blotchy red rash on the cheeks with groups of red papules.
- After 4 days, a net of red marks may appear on the arms and trunk.
- In the third stage, the rash only appears after exposure to sunlight or heat.
Impetigo is a highly contagious skin infection that most commonly affects children. The first sign is normally a patch of red, itchy skin. There are two types of impetigo:
- Non-bullous impetigo – red sores appear around the mouth and nose.
- Bullous impetigo – less common, generally affects children under 2. Medium to large blisters appear on the trunk, arms, and legs.
Shingles is an infection of an individual nerve. It is caused by the same virus as chickenpox – the varicella-zoster virus. Symptoms include:
- A rash similar to chickenpox in a band around the infected nerve.
- Blisters can merge producing a solid red band.
- Rash is often painful.
Scabies is a skin condition caused by a microscopic mite. It is very contagious and spreads easily through person-to-person contact. Symptoms include:
- Intense itching – often worse at night.
- Rash – appears in lines as the mite burrows. Blisters are sometimes present.
- Sores – may appear where the rash has been scratched.
Eczema is one of the most common skin conditions. It often first develops in childhood. Symptoms depend on the type of eczema and on the age of the individual but they often include:
- dry scaly patches on the skin
- intensely itchy rash
- cracked and rough skin
8. Hay fever
- runny nose
- watery eyes
Hay fever can also cause a rash, similar to hives. These will appear as itchy red patches or eruptions on the skin.
9. Scarlet fever
Scarlet fever is a disease caused by a toxin released by a bacteria – Streptococcus pyogenes – the same bacteria that is responsible for Strep throat. Symptoms include a sore throat, rash, and fever. The rash has the following characteristics:
- red blotches
- blotches turn to fine pink-red rash like sunburn
- skin feels rough
10. Rheumatic fever
Rheumatic fever is an inflammatory reaction to a streptococcal infection, such as Strep throat. It most commonly affects children aged 5-15. Symptoms include:
- small painless bumps under skin
- red skin rash
- swollen tonsils
11. Mono (mononucleosis)
Mono, or mononucleosis, is caused by a virus. It is rarely serious, but symptoms can include:
- a pink, measle-like rash
- body aches
- high fevers
Ringworm, despite its name, is caused by a fungus. The fungal infection affects the top layer of the skin, scalp, and nails. Symptoms vary depending on the site of the infection, but can include:
- itchy, red rash in rings – sometimes slightly raised
- small patches of scaly skin
- hair near patches breaks away
Measles is a highly contagious disease caused by the rubeola virus. Symptoms include:
- a reddish-brown rash
- small grayish-white spots with bluish-white centers in the mouth
- dry cough
14. Yeast infection (candidiasis)
Candidiasis is a common fungal infection of the genitals. It affects both sexes, but more commonly, women. Symptoms include:
- pain and soreness in the genital area
- itching, burning, and irritation
15. Stasis dermatitis
Stasis dermatitis is also known as varicose eczema. It develops due to poor circulation and most commonly affects the lower legs. Symptoms include:
- varicose veins covered in itchy, dry skin
- red, swollen, painful skin, which may weep or crust over
- heavy, aching legs after standing for some time
16. German measles
Also known as rubella, German measles are an infection caused by the rubella virus. Symptoms include:
- rash – less bright than measles, often begins on the face
- inflamed, red eyes
- stuffy nose
Sepsis, often called blood poisoning, is a medical emergency. It is the result of a wide scale immune response to an infection. Symptoms vary, but can include:
- a rash that does not fade under pressure
- increased heart rate
18. West Nile virus
West Nile virus is an infection spread by mosquitos. Often, there are no symptoms, but if they do occur, they can include:
- raised and/or flat, pink skin rash on the trunk, arms, or legs
- excessive sweating
19. Lyme disease
Lyme disease is a bacterial infection transmitted to humans by the bite of an infected tick. The symptoms include an erythema migrans rash that often appears in the early stages of the disease.
- The rash begins as a small red area that may be warm to the touch but not itchy.
- The center loses color, giving it a bull’s-eye appearance.
- The rash does not necessarily appear at the site of the tick bite.
Cellulitis is a bacterial infection of the deep layer of skin – the dermis. It normally occurs when bacteria enter through a break in the skin. Symptoms include:
- Skin sores or rash that starts suddenly and grows quickly.
- Warm skin around the redness.
- Fever and fatigue.
MRSA (methicillin-resistant staphylococcus aureus) is a contagious bacterial infection that is resistant to a range of antibiotics. This makes it difficult to treat. Symptoms include:
- swelling and tenderness in the affected part of the body
- wounds that do not heal
Photo credit: National Institute of Allergy and Infectious Diseases (NIAID)
Chickenpox is an infection by the varicella zoster virus. It is unpleasant, but most people recover within a couple of weeks. Symptoms include:
- An itchy rash of small red spots first appears on the face and trunk, and then spreads across the body.
- Spots then develop blisters on top.
- After 48 hours, the blisters cloud and start to dry out.
Lupus is an autoimmune disease, meaning that the immune system attacks healthy tissue. Symptoms vary widely from person to person, but can include:
- Butterfly-shaped rash across the cheeks and the bridge of the nose.
- Flaky red spots or a purple, scaly rash on the face, neck, or arms.
- Skin sensitivity to the sun.
24. Toxic shock syndrome
Toxic shock syndrome is a rare condition sparked by a bacterial infection. It develops quickly and can be life-threatening. All people who have toxic shock syndrome have fever and a rash with the following characteristics:
- looks similar to sunburn and covers most of the body
- flat not raised
- turns white when pressed
25. Acute HIV infection
During the first stages of HIV, levels of the virus in the blood are very high because the immune system has not yet started tackling the infection. Early symptoms include a rash with the following features:
- mostly affects the upper part of the body
- flat or barely raised small red dots
- not generally itchy
26. Hand, foot, and mouth
Hand, foot, and mouth is a childhood illness resulting from a viral infection. Symptoms include:
- Rash – flat, non-itchy red blisters on the hands and soles of the feet.
- Loss of appetite.
- Ulcers on the throat, tongue, and mouth.
Image credit: KlatschmohnAcker
Acrodermatitis, a type of pustular psoriasis, is also known as Gianotti-Crosti syndrome. It is associated with viral infections. Symptoms include:
- itchy purple or red blisters
- swollen lymph nodes
- bloated abdomen
Hookworm is a common intestinal parasite. It can cause a range of complications. Symptoms include:
- Skin rash in one particular area that is red, itchy, and raised.
- Breathing complications.
- Extreme tiredness.
29. Kawasaki disease
Kawasaki’s disease is a rare syndrome that affects children. It is characterized by an inflammation of the walls of the arteries throughout the body. Symptoms include:
- A rash on the legs, arms, and torso and between the genitals and anus.
- A rash on the soles of the feet and palms of the hand, sometimes with peeling skin.
- Swollen, chapped, and dry lips.
Syphilis is a sexually transmitted bacterial infection. The disease is treatable, but will not go away on its own. Symptoms vary depending on the stage of the disease and include:
- Initially – painless, firm, and round syphilitic sores (chancres).
- Later – non-itchy red/brown rash that starts on the trunk and spreads across the body.
- Oral, anal, and genital wart-like sores.
Typhoid is caused by a bacterial infection. It is spread quickly by contact with the feces of an infected person. If untreated, 25 percent of cases end in death. Symptoms can include:
- Rash – rose-colored spots, especially on the neck and abdomen.
- Fever – up to 104 degrees Fahrenheit.
- Abdominal pain, diarrhea, and constipation.
Image credit: Charles N. Farmer, CDC/ Armed Forces Institute of Pathology, 1964
32. Dengue fever
Dengue fever, also called breakbone fever, is transmitted by mosquitos. The condition ranges from mild to severe. Symptoms can include:
- Initially a flat, red rash appears over most of the body.
- Later, a secondary rash appears, similar to measles.
- Severe joint and muscle aches.
Image credit: calliopejen, 2009
Ebola is a serious viral disease; it spreads rapidly through families and friends and can often be fatal. Often, a rash is one of the symptoms:
- Initially, a short-lived mild rash may be present.
- Rashes begin to peel and look like sunburn.
- Later in the disease, the rash may turn to abscesses.
Severe acute respiratory syndrome (SARS) is a contagious and sometimes fatal respiratory illness. Symptoms can include:
- skin rash
- stiff muscles
35. Contact dermatitis
Contact dermatitis occurs when the skin comes in contact with an irritant; it is relatively common, and can be unpleasant. Symptoms include:
- red, flaky rash that stings
- blistered skin
- burning sensation
- cracked skin
36. Fungal infection
Although some fungi live naturally on the human body, sometimes, they can overtake. Symptoms depend on where the infection strikes, but can include:
- a red rash with a circular shape and raised edges
- cracking, flaking, or dry peeling of the skin in the infected area
- chafing, irritation, itching, or burning in the infected area
37. Drug allergy
Certain people have allergic reactions to prescribed drugs. The body’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:
- Rash, including hives
- Itchy skin or eyes
38. Atypical pneumonia
Also called walking pneumonia, atypical pneumonia is less severe than the typical form. Symptoms can include:
- rashes (uncommon)
- weakness and fatigue
- chest pain, especially when breathing deeply
Erysipelas is a skin infection. It is a form of cellulitis, however, unlike cellulitis, it only affects the upper layers of the skin, rather than deeper tissue. The skin in a particular area becomes:
- swollen, red, and shiny
- tender and warm to the touch
- red streaks above the affected area
Image credit: CDC/Dr. Thomas F. Sellers/Emory University
40. Reye’s syndrome
Reye’s syndrome is rare and most commonly occurs in children. It can cause serious damage to the body’s organs, particularly the brain and liver (image opposite shows fat accumulation in liver cells). Early symptoms include:
- Rash on the palms of the hands and feet.
- Repeated, heavy vomiting.
- Lethargy, confusion, and headaches.
41. Addisonian crisis
Addisonian crisis – also known as an adrenal crisis and acute adrenal insufficiency – is a rare and potentially fatal condition where the adrenal glands stop working correctly. Symptoms include:
- skin reactions, including rashes
- low blood pressure
- fever, chills, and sweating
42. Chemical burns
Chemical burns are relatively common; they can occur when a person comes in direct contact with a chemical or its fumes. Symptoms vary but can include:
- skin that appears black or dead
- irritation, burning, or redness in the affected area
- numbness and pain
43. Colorado tick fever
Colorado tick fever, also known as mountain tick fever and American tick fever is a viral infection that develops after a bite from a Rocky Mountain wood tick. Symptoms can include:
- a flat or pimply rash
- skin or muscle pain
44. Accidental poisoning by soap products
Some soap products contain strong chemicals. If they are ingested or inhaled, they can cause serious damage. Symptoms can include:
- chemical burns on the skin
- swelling of the throat, lips, and tongue
- difficulty breathing
45. Adult-onset Still’s disease
Adult-onset Still’s disease is a rare inflammatory disorder that usually affects people in their 30s. Symptoms include:
- A pink rash, mostly affecting the chest and thighs, which tends to fade quickly.
- Joint and muscle pain, commonly affecting the knees, wrists, and ankles.
- Enlarged spleen, liver, or lymph nodes.
46. Juvenile idiopathic arthritis
- fleeting rashes
- a scaly psoriasis-like rash
- spiking fever
Histoplasmosis is a fungal infection of the lungs. Sometimes, it presents no symptoms, but in other cases, it produces pneumonia-like symptoms; these include:
- chest pain
- red bumps on lower legs
Dermatomyositis is a medical condition that causes muscle weakness and rashes. The rash may be red and patchy or bluish-purple in color; it appears in a number of places, including:
- shoulders and upper back
- palms and fingers
- around the eyes
49. Graft-versus-host disease
People being treated for certain cancers may sometimes undergo a stem cell transplant; in some cases, the donor cells attack the recipient’s healthy cells instead of the cancer cells. Symptoms can include:
- Rashes affecting the palms of the hands, soles of the feet, ears, or face.
- Other skin changes, such as drying, scaling, scarring, hardening, and darkening.
- Hair loss.
50. Icthyosis vulgaris
Ichthyosis vulgaris is a hereditary skin condition that often begins in childhood. It is caused by a mutation in the gene that codes for the protein filaggrin; features include:
- The skin’s surface becomes dry, thick, and scaly.
- The dryness is often accompanied by fine, white, or skin-colored scales.
- It commonly affects the elbows, shins, face, scalp, and torso.
Pemphigoid is a group of rare autoimmune conditions that primarily cause rashes and skin blistering; there are three main types:
- Bullous pemphigoid – blistering on the lower torso, groin, armpits, inner thighs, soles, and palms.
- Cicatricial pemphigoid – mostly affects mucous membranes.
- Pemphigoid gestationis – develops during pregnancy and mostly affects the upper body.
Sarcoidosis is a condition involving the growth of persistent or inappropriate granulomas or clumps of inflammatory cells. Symptoms include:
- Erythema nodosum – a raised red rash on the lower extremities.
- Nodules or growths under the skin, especially around scar tissue.
- Skin discoloration.
Phenylketonuria is a genetic condition that affects how phenylalanine is broken down by the body. It affects around 1 in 10,000 babies in the U.S. If left untreated, phenylalanine builds up, causing:
- skin rashes, such as eczema
- lighter skin and eyes due to abnormal levels of melanin
Porphyria refers to a group of genetic disorders that can affect the nervous system or the skin; symptoms are varied but can include:
- redness and swelling on the skin
- burning pain on the skin
- changes in skin pigmentation
55. Dermatitis neglecta
Dermatitis neglecta is a skin disorder that arises when an individual does not clean themselves sufficiently. It can look similar to other allergic conditions. Symptoms include patches of scaly skin that are collections of:
- sweat and moisture
- bacteria and other germs
Image credit: Dr. Piotr Brzezinski Ph.D.
56. Heliotrope rash
Heliotrope rash is often the first noticeable symptom of an inflammatory muscle disease called dermatomyositis. The rash often includes:
- raised and bumpy skin
- red patches
- skin looks dry and irritated
Image credit: Elizabeth M. Dugan, Adam M. Huber, Frederick W. Miller, Lisa G. Rider, 2010.
57. Uric acid skin rash
A person may develop a rash when high levels of uric acid in the blood cause crystals to form and accumulate in and around a joint. This can also lead to gout. Symptoms include:
- A dotted rash on the surface of the skin
- Redness, tenderness, and swelling of the joints
- Prolonged joint pain for weeks following the reaction
Image credit: WNT.
1. Amoxicillin reaction
Some people are allergic to the antibiotic amoxicillin. If a person experiences any of the following symptoms they should stop taking it and report to their doctor:
- skin rash
- blotchy skin
Image credit: Skoch3, 2008.
2. Erythema ab igne (hot bottle rash)
Erythema ab igne is caused by overexposure to heat. Regularly using hot water bottles, or other forms of heat, to relieve pain from muscle or joint damage may lead to developing this skin condition.
Image credit: James Heilman, MD, 2010.
3. Ketoconazole shampoo reaction
Applying ketoconazole shampoo to the scalp can help reduce skin conditions such as dandruff and psoriasis. If a person has an allergic reaction to ketoconazole their symptoms may include:
- enflamed rash covering the area that came into contact with the shampoo
Image credit: Niels Olson, 2010.
4. Beard dye reaction
Some people are allergic to chemicals found in beard or hair coloring dye. Symptoms of an allergic reaction include:
- dry, flaky skin
Image credit: Yngve Roennike, 2016.
5. Infant milk rash
Breastfed babies may develop a rash if they are allergic to a food group that their mother is consuming. Symptoms of a food allergy can include:
6. Urticaria (nettle rash)
A person with urticaria will likely develop a raised, itchy rash that is usually triggered by an allergen. Common symptoms of urticaria include:
- pink wheals (swellings) on the skin
- extreme itchiness
7. Grass allergy
A person with a grass allergy may develop hay fever symptoms when coming into contact with grass. It is also common to experience:
- small red dots on the skin
Image credit: Carolyn, 2009.
8. Poison ivy reaction
Coming into contact with poison ivy plant oil can lead to a person developing contact dermatitis. Symptoms of this include:
- small bumps or blisters on the skin
Image credit: CDC/ Richard S. Hibbits, 1971.
9. Smallpox vaccination reaction
Following a vaccination, some people may develop the following symptoms:
- small bumps
Image credit: CDC/ Arthur E. Kaye, 1969.
10. Hyposensitization therapy reaction
Hyposensitization therapy is used to treat allergic disease. While receiving the course of injections, a person may experience the following symptoms:
Image credit: Bionerd, 2008.
11. Euproctis chrysorrhoea (brown-tail moth) reaction
A person may develop a rash after touching a brown-tail moth. This is caused by a reaction to the toxins found in the moth’s hairs. Symptoms include:
- red, blotchy skin
- raised bumps
Image credit: B kimmel, 2010.