The best ways to diagnose a skin rash includes laboratory tests and special examinations, according to eMedicineHealth. Microscopic examinations, patch tests, blood tests, grain stain and skin biopsies are effective ways to diagnose skin rashes. Different skin rashes have distinct characteristics that are diagnosed using specific laboratory tests and examinations.
One of the best ways to diagnose skin rash involves skin sampling. This method involves viewing skin under a microscope, which provides a quick and simple method of diagnosing a rash. Microscopy consists of observing fungus, and performing potassium hydroxide prep to reveal budding cells or fungal hyphae, as stated by eMedicineHealth.
Both nasal swabs and Gram stains are useful for detecting bacterial infection. This method evaluates the skin for bacteria, and observes viral lesions, per eMedicineHealth. In some cases, multinucleate cells are detected, which displays characteristics of a specific type of skin rash.
Another way to diagnose different types of skin rash involve performing a blood test. This type of test is helpful for diagnosing severe psoriasis, and other onset symptoms that are associated with specific types of infection, according to eMedicineHealth. This test detects anti-streptolysin O levels, which is associated with identifying symptoms of sudden onset guttate psoriasis.