Nodular scabies lesions on a patient's scrotum. Scabies is an infestation by the Sarcoptes scabiei mite. The female mite tunnels in the skin to lay eggs. The mite's burrows are tiny, grey scaly swellings on the skin. Later, reddish lumps may appear on the limbs and trunk. The infestation causes intense itching, and scratching results in sores. The condition can give rise to the nodular lesions seen here.