Many viral infections can cause a rash in addition to other symptoms. Rashes are very common with viral infections, especially in young children. It is very important to make sure the rash is not part of a serious infection - eg, meningococcal infection. If you have any concerns then you should contact your GP immediately.
What is a viral rash?
The symptoms caused by viral infections can vary depending upon the virus. One of the symptoms that may occur is a rash. There are some well-known viral rashes. For example, the measles virus and the chickenpox virus cause characteristic rashes along with other symptoms. Sometimes a typical rash helps a doctor to diagnose which virus is causing an illness.
Many viruses can cause a rash in addition to other symptoms such as fever and cough. Many of these rashes are 'nonspecific'. This means the rash is not specific or characteristic enough to identify the virus that is causing the rash. The doctor cannot say which virus is the culprit, but that some virus is a likely cause of the rash.
Viral rashes vary in shape and size. However, they often appear as blotchy red spots. Commonly they affect most of the body. Sometimes they appear dramatically. For example, you may wake up in the morning to find yourself covered in a rash. It usually lasts only a few days. Sometimes the rash is slightly itchy. Usually the rash disappears without trace within a few days. There are a great variety of types.
Are viral rashes serious?
The viral rash itself is not usually serious. But it is very important to make sure the rash is not part of a serious infection - eg, meningococcal infection. If you have any concerns then you should contact your GP immediately.
What matters is whether other symptoms or problems occur. For example, the measles virus can cause a nasty illness with a chest infection, severe diarrhoea, etc, in addition to a rash. However, many viruses cause only minor symptoms - perhaps a mild fever or slight cough - but the rash may look quite dramatic. Sometimes the rash appears just as the other symptoms are improving.
Pregnant women - most viral infections causing a rash will do no harm to the developing baby. However, some may do. For example, the rubella (German measles) virus. It is therefore best for pregnant women to avoid people who have an infectious rash. Also, if you are pregnant and develop a rash, it is best to see a doctor for advice.
The sudden appearance of a widespread blotchy rash is quite common. It is often due to a viral infection. It is the other symptoms that may be of more concern. If other symptoms are mild then there is usually little to worry about. It will usually go in a few days. There is no specific treatment for the rash itself. Treatment should be aimed at the other symptoms. For example, paracetamol can be used for high temperatures, etc.
See a doctor if you are concerned that a rash or other symptoms may be serious.
Dr Tim Kenny
Dr Colin Tidy
Prof Cathy Jackson