Rash: Overview

The causes of a rash on the skin are many. There are literally hundreds and it can take some time for a doctor to consider them all.

Many different contagious infections cause some type of rash, such as roseola, measles, chicken pox, parvovirus, and many others. A blistering pustular rash may be caused by various skin conditions, such as boils, folliculitis, acne, rosacea, shingles, and many others.

Harmless causes may include things like a reaction to some plant you accidentally rubbed against in the garden (dermatitis). But on the other hand, there are also severe diseases that must be ruled out, such as a hemorrhagic rash that occurs in meningococcal disease (which is a medical emergency). Another possible cause of a rash is a side-effect of a medication that you may be taking.

A rash needs to be differentiated against other similar symptoms such as facial redness (e.g. flushing), bruises, insect bites, under-skin bleeding, petechiae, cysts, warts, sunburns, chilblains, and various other causes of skin discolorations.

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Back to: « Rash

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Summary

A red eruption of the skin. [from HPO]

Source: GTR (NCBI/NIH)1

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There are many different kinds of rash. They have a variety of causes, such as diseases, allergies and fungal infections.

Source: New Zealand Health2

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A rash causes reddening of the skin and can be itchy.

There are many different kinds of rash. They have a variety of causes - such as diseases, allergies and fungal infections.

Source: New Zealand Health3

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A rash is an area of irritated or swollen skin. Many rashes are itchy, red, painful, and irritated. Some rashes can also lead to blisters or patches of raw skin. Rashes are a symptom of many different medical problems. Other causes include irritating substances and allergies. Certain genes can make people more likely to get rashes.

Contact dermatitis is a common type of rash. It causes redness, itching, and sometimes small bumps. You get the rash where you have touched an irritant, such as a chemical, or something you are allergic to, like poison ivy.

Some rashes develop right away. Others form over several days. Although most rashes clear up fairly quickly, others are long-lasting and need long-term treatment.

Because rashes can be caused by many different things, it's important to figure out what kind you have before you treat it. If it is a bad rash, if it does not go away, or if you have other symptoms, you should see your health care provider. Treatments may include moisturizers, lotions, baths, cortisone creams that relieve swelling, and antihistamines, which relieve itching.

Source: MedLinePlus (NIH)4

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We often think of the skin as a barrier—it keeps the insides of our bodies in, and it keeps the outside world out. But our skin is also filled with special cells of the immune system. These cells protect the skin and body against viruses, bacteria and other threats. Whenever these cells detect a suspicious substance, they begin a chain reaction in the skin that leads to inflammation. The medical name for this reaction is dermatitis. But it’s more commonly known as a rash.

Source: NIH News in Health (NIH)5

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Skin Rash: Any change in the skin which affects its appearance or texture. A rash may be localized to one part of the body, or affect all the skin. Rashes may cause the skin to change color, itch, become warm, bumpy, dry, cracked or blistered, swell and may be painful.6

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Skin rash: A red eruption of the skin.7

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Rash: A skin and integumentary tissue symptom characterized as an eruption on the body typically with little or no elevation above the surface.8

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Rash adverse event: A skin adverse event that shows the symptom of rash, i.e., an abnormal change in skin color, appearance, or texture. A rash may cause the skin to change color, itch, become warm, bumpy, dry, cracked or blistered, swell and may be painful.9

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References

  1. Source: GTR (NCBI/NIH): ncbi.nlm.nih.gov/ gtr/ conditions/ CN000925/ 
  2. Source: New Zealand Health: health.govt.nz/ your-health/ conditions-and-treatments/ diseases-and-illnesses
  3. Source: New Zealand Health: health.govt.nz/ your-health/ conditions-and-treatments/ diseases-and-illnesses/ rashes
  4. Source: MedLinePlus (NIH): medlineplus.gov/ rashes.html
  5. Source: NIH News in Health (NIH): newsinhealth.nih.gov/ issue/ apr2012/ feature1
  6. Source: NCI Thesaurus
  7. Source: Human Phenotype Ontology
  8. Source: SYMP Ontology
  9. Source: OAE Ontology

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Note: This site is for informational purposes only and is not medical advice. See your doctor or other qualified medical professional for all your medical needs.