Symptoms of scabies first begin to appear around 4 to 6 weeks after initial exposure. The hallmark of scabies is intense itching, which is usually worse at night. The burrows of the mites are often visible as very thin lines up to a ½ inch (about 1 centimeter) long, sometimes with a tiny reddish and very itchy bump—the mite—at one end. Learn more: https://mrkmnls.co/4oavuBN | Merck Manual Consumer