Measles (Rubeola) Sign
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.