Rash is a general, nonspecific term that describes any visible skin outbreak. Rashes are very common in all ages, from infants to seniors, and nearly everyone will have some type of rash at some point in their life. There are a wide variety of medical diagnoses for skin rashes and many different causes. It is not possible to fully cover every type of rash in this type of article. Therefore, special mention has been given here to some of the most common types of rashes. A dermatologist is a medical provider who specializes in diseases of the skin and may need to be consulted for rashes that are difficult to diagnose and treat.
While there are many different types, rashes may basically be divided into two types: infectious or noninfectious.
Noninfectious rashes include eczema, contact dermatitis, psoriasis, seborrheic dermatitis, drug eruptions, rosacea, hives (urticaria), dry skin (xerosis), and allergic dermatitis. Many noninfectious rashes are typically treated with corticosteroid creams and/or pills. Even a noncontagious, noninfectious rash can cause discomfort and anxiety.
Infection-associated rashes, such as ringworm (tinea), impetigo, Staphylococcus, scabies, herpes, chickenpox, and shingles, are treated by treating the underlying cause. Infectious agents that can cause a rash include viruses, bacteria, fungi, and parasites.
Determining the specific cause of rash usually requires a description of the skin rash, including its shape, arrangement, distribution, duration, symptoms, and history. All of these factors are important in identifying the correct diagnosis. Accurate information about past treatments, successful and unsuccessful, is very important. Treatments that work may be a clue to the cause of the rash, may mask symptoms, or change the appearance, making a definite diagnosis harder. Sometimes good quality pictures of an earlier stage of the rash may aid diagnosis.
Many different risk factors determine what rash or rashes a patient might get. A family history of eczema, frequent exposure to sick children, necessary use of immunosuppressive medications, and exposure to multiple medications all increase the risk of developing rashes.
A careful drug history that includes over-the-counter (OTC) medications, supplements, and prescription drugs such as birth control pills is also important. The timing of when medications are started and stops may provide important clues for establishing the cause of a rash.
There are some rashes that only appear in association with pregnancy, either during pregnancy or even after the delivery of the baby. Most of these are not serious but can be very irritating.
The reported history will help characterize the duration, onset, relationship to various environmental factors, skin symptoms (such as itching and pain), and constitutional symptoms such as fever, headache, and chills. Based on the health-care provider's initial impression of a rash, treatment may be started. The treatment may need to be modified pending various laboratory and special skin examinations.
Medically Reviewed by a Doctor on 7/21/2015
Jeffrey John Meffert, MD
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