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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
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
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.
Based on your answers, you need
or other emergency services now.
Based on your answers, you may need care right away. The problem is likely to get worse without medical care.
Based on your answers, the problem may not improve without medical
Based on your answers, you may need care soon. The
problem probably will not get better without medical care.
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.
Many prescription and nonprescription medicines can cause a
rash. A few common examples are:
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:
Symptoms of infection may
Symptoms of serious illness may
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.
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
Ear or rectal temperature
Armpit (axillary) temperature
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:
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”):
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.
Certain health conditions and medicines weaken the immune system's ability to fight off infection and
illness. Some examples in adults are:
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
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.
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
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
Current as of:
June 4, 2014
William H. Blahd, Jr., MD, FACEP - Emergency Medicine
& H. Michael O'Connor, MD - Emergency Medicine
How this information was developed to help you make better health decisions.
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