Healthy skin provides a barrier between the inside of the body and the outside environment. A rash means some change has affected the skin.
Rashes are generally caused by skin irritation, which can have many causes. A rash is generally a minor problem that may go away with home treatment. In some cases a rash does not go away or the skin may become so irritated that medical care is needed.
In adults and older children, rashes are often caused by contact with a substance that irritates the skin (contact dermatitis). The rash usually starts within 48 hours after contact with the irritating substance. Contact dermatitis may cause mild redness of the skin or a rash of small red bumps. A more severe reaction may cause swelling, redness, and larger blisters. The location of the rash may give you a clue about the cause.
Contact dermatitis does not always occur the first time you are in contact with the irritating substance (allergen). After you have had a reaction to the substance, a rash can occur in response to even very small amounts of the substance. Contact dermatitis is not serious, but it is often very itchy. Common causes of contact dermatitis include:
Rashes may occur with viral infections, such as herpes zoster; fungal infections, such as a yeast infection (Candida albicans); bacterial infections, such as impetigo; and sexually transmitted infections (STIs). Rashes may also occur as a symptom of a more serious disease, such as liver disease, kidney disease, or some types of cancer.
Rashes may also appear after exposure to an insect or a parasite, such as the scabies mite. You may develop a rash when you travel to a rural area or go hiking or camping in the woods.
A rash may be a sign of a chronic skin problem, such as acne, eczema, psoriasis, or seborrheic dermatitis. Other causes of rash include dry, cold weather; extremely hot weather (heat rash); and emotional stress. Emotions such as frustration or embarrassment may lead to an itchy rash.
Some medicines can cause a rash as a side effect. A very rare and serious type of generalized red rash called toxic epidermal necrolysis (TEN) may occur after using sulfa drugs. TEN can cause the skin to peel away, leaving large areas of tissue that weep or ooze fluid like a severe burn. TEN may occur after the use of some medicines. If this type of rash occurs, you need to see a doctor.
The need for medical treatment often depends on what other symptoms are present. A rash that occurs with other symptoms, such as shortness of breath or fever, may mean another problem, such as a serious allergic reaction or infection.
Check your symptoms to decide if and when you should see a doctor.
Many things can affect how your body responds to a symptom and what kind of care you may need. These include:
You have answered all the questions. Based on your answers, you may be able to take care of this problem at home.
Sudden tiny red or purple spots or sudden bruising may be early symptoms of a serious illness or bleeding problem. There are two types.
Petechiae (say "puh-TEE-kee-eye"):
Purpura (say "PURR-pyuh-ruh" or “PURR-puh-ruh”):
If you're not sure if a fever is high, moderate, or mild, think about these issues:
With a high fever:
With a moderate fever:
With a mild fever:
Temperature varies a little depending on how you measure it. For adults and children age 12 and older, these are the ranges for high, moderate, and mild, according to how you took the temperature.
Oral (by mouth) temperature
A forehead (temporal) scanner is usually 0.3 C (0.5 F) to 0.6 C (1 F) lower than an oral temperature
Ear or rectal temperature
Armpit (axillary) temperature
Certain health conditions and medicines weaken the immune system's ability to fight off infection and illness. Some examples in adults are:
Abnormal bleeding means any heavy or frequent bleeding or any bleeding that is not normal for you. Examples of abnormal bleeding include:
When you have abnormal bleeding in one area of your body, it's important to think about whether you have been bleeding anywhere else. This can be a symptom of a more serious health problem.
Symptoms of serious illness may include:
Symptoms of infection may include:
Shock is a life-threatening condition that may quickly occur after a sudden illness or injury.
Symptoms of shock (most of which will be present) include:
Many prescription and non-prescription medicines can cause a rash. A few common examples are:
Symptoms of a severe allergic reaction (anaphylaxis) may include:
A severe reaction can be life-threatening. If you have had a bad allergic reaction to a substance before and are exposed to it again, treat any symptoms as an emergency. Even if the symptoms are mild at first, they may quickly become very severe.
Based on your answers, you may need care soon. The problem probably will not get better without medical care.
Based on your answers, the problem may not improve without medical care.
Based on your answers, you may need care right away. The problem is likely to get worse without medical care.
Based on your answers, you need emergency care.
or other emergency services now.
Most rashes will go away without medical treatment. Home treatment can often relieve pain and itching until the rash goes away.
If you have come in contact with a substance such as poison ivy, oak, or sumac, immediately wash the area with large amounts of water.
After a rash has developed, leave it alone as much as possible.
If you have a rash, you should not be in contact with children or pregnant women. Most viral illnesses that cause a rash are contagious, especially if a fever is present.
Carefully read and follow all label directions on the medicine bottle or box.
Talk to your child's doctor before switching back and forth between doses of acetaminophen and ibuprofen. When you switch between two medicines, there is a chance your child will get too much medicine.
Call your doctor if any of the following occur during home treatment:
If you have a known allergy, avoid contact with the substance that causes the allergy.
Avoid all infectious diseases that cause skin rashes, such as chickenpox, measles, and some types of sexually transmitted infections (STIs).
To prepare for your appointment, see the topic Making the Most of Your Appointment.
You can help your doctor diagnose and treat your condition by being prepared to answer the following questions:
ByHealthwise StaffPrimary Medical ReviewerWilliam H. Blahd, Jr., MD, FACEP - Emergency MedicineKathleen Romito, MD - Family MedicineAdam Husney, MD - Family MedicineE. Gregory Thompson, MD - Internal MedicineSpecialist Medical ReviewerH. Michael O'Connor, MD - Emergency Medicine
Current as ofJune 14, 2017
Current as of: June 14, 2017
William H. Blahd, Jr., MD, FACEP - Emergency Medicine
& Kathleen Romito, MD - Family Medicine & Adam Husney, MD - Family Medicine & E. Gregory Thompson, MD - Internal Medicine & H. Michael O'Connor, MD - Emergency Medicine
To learn more about Healthwise, visit Healthwise.org.
© 1995-2017 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.