Symptoms of an Infection

The scabies itch is often severe and is usually worse at night and while bathing. Visible symptoms include rash and bumps between the fingers; inside the wrists, elbows, or knees; in the skin creases of the buttocks and groin; around the navel and nipples (especially in women); on the feet; and on external genitalia.

The bumps contain nests for hatching and growing mites. They can become inflamed, crusty, and hard, and can persist for weeks after treatment. The burrows may appear as short, zigzag, grayish lines under the skin. Scabies is a local infection with no known systemic complications. The itching and rash will intensify and spread without treatment. Scratching often produces secondary bacterial infection, pus-filled lesions, and cracks in the skin.

Diagnosis

Diagnosis is made by physical examination. Scabies lesions can be scraped to obtain a sample of tissue, which is mixed with potassium hydroxide (KOH) and examined under a microscope for eggs, feces, and mites. This test confirms the diagnosis and rules out other skin diseases that cause itching.