A rash is an area of the skin that has broken out or changed in appearance. It may affect one small patch of skin or the entire body.
There are many skin changes that can occur with a rash, including:
Skin can react or break out for many different reasons, ranging from allergic reactions to infections and even cancer.
There are many possible causes of a rash. General categories include:
Other causes are also possible. Sometimes the cause is not found.
There are many questions a healthcare provider may have when someone complains of a rash. For instance, he or she may ask:
The healthcare provider may ask about other symptoms, which can help narrow the list of possible causes. For instance, a person may be asked about his or her sexual history or whether he or she has had arthritis or weight loss.
The cause of some rashes can be diagnosed after a history and examination of the rash. Other rashes may be more difficult to identify. Further tests may be needed, including blood or urine tests. Sometimes, a biopsy of the affected skin is needed. This involves removing a small piece of skin with a special tool. The skin can then be analyzed in the lab to help determine the cause.
Further tests may be needed in some cases, depending on the suspected cause. For instance, the provider may order a chest X-ray if he or she suspects that a lung infection is causing the rash.
Prevention of a rash depends on the cause, which is often difficult to diagnose. Those with allergies should avoid the substances they are allergic to whenever possible. Routine childhood vaccines can prevent some infections that cause a skin rash, such as measles and chickenpox. Avoiding the sun and using sunscreen can reduce the risk of skin cancer.
Some rashes, such as severe acne, may cause permanent scarring of the skin. Other rashes may become infected because of skin breakdown. In very rare cases, such as with severe allergic skin reactions, rashes can even result in death.
For most rashes, the long-term effects are related to the underlying cause. For instance, cancer or serious infections that cause rashes may result in death. Rashes associated with pregnancy often go away after delivery and have no long-term effects.
In some cases, a rash can be contagious and spread to others. In most cases, however, a rash poses no risk to others.
Affected skin should be kept clean, especially if there is skin breakdown. Specific treatment depends on the cause. For instance, those with infections may need antibiotic pills or creams applied to the rash. Those with allergic reactions may need antihistamines or corticosteroid pills or creams. Those with autoimmune disorders may need medications to suppress the immune system. Those with cancer or poor circulation may need surgery.
Medications may cause allergic reactions, stomach upset, and headaches. Specific side effects depend on the medications used. For instance, antihistamines often cause drowsiness. Surgery may cause bleeding, infection, or allergic reaction to anesthesia.
If the rash goes away, an individual may or may not need further treatment. For instance, those with diabetes or poor circulation need further treatment and monitoring even after their rashes go away. Those who have ringworm, a fungal infection of the skin, are cured after treatment. They can return to normal activities without further treatment.
People can monitor their own rashes at home. Those with skin breakdown need to watch for infection until the skin heals over. The provider may also want to monitor the rash periodically, depending on the cause. Any new or worsening symptoms should be reported to the healthcare provider.
Author:Adam Brochert, MD
Date Written:
Editor:Ballenberg, Sally, BS
Edit Date:02/12/01
Reviewer:Eileen McLaughlin, RN, BSN
Date Reviewed:07/27/01
Cecil's Textbook of Medicine, 1996, Bennett et al.
Harrison's Principles of Internal Medicine, 1998, Fauci et al.