Scabies: Signs and symptoms
What are the signs and symptoms of scabies?
After the mite burrows into the skin, it takes time to develop signs and symptoms. If you've had scabies before, the itching usually begins within one to four days. When a person has not had scabies, the body needs time to develop a reaction to the mite. It can take two to six weeks to develop symptoms.
Scabies on a hospitalized patient
While spending time in a rehabilitation facility, this 75-year-old man developed scabies.
Signs and symptoms of scabies include:
Itching, mainly at night: Itching is the most common symptom. The itch can be so intense that it keeps a person awake at night.
Rash: Many people get the scabies rash. This rash causes little bumps that often form a line. The bumps can look like hives, tiny bites, knots under the skin, or pimples. Some people develop scaly patches that look like eczema.
Sores: Scratching the itchy rash can cause sores. An infection can develop in the sores.
Thick crusts on the skin: Crusts form when a person develops a severe type of scabies called crusted scabies. Another name for crusted scabies is Norwegian scabies. With so many mites burrowing in the skin, the rash and itch become severe. You'll find more information about crusted scabies below.
The severe itch can lead to constant scratching. With non-stop scratching, an infection can develop. Non-stop scratching can even lead to sepsis, a sometimes life-threatening condition that develops when the infection enters the blood.
Scabies can develop anywhere on the skin. The mites, however, prefer to burrow in certain parts of the body. The most common places to have itching and a rash are:
Hands: Mites like to burrow in the skin between the fingers and around the nails.
Arms: Mites like the elbows and wrists.
Skin usually covered by clothing or jewelry: The buttocks, belt line, penis, and skin around the nipples are likely places for mites to burrow. Mites also like to burrow in skin covered by a bracelet, watchband, or ring.
In adults, the mites rarely burrow into skin above the neck.
Scabies in children
Some children develop widespread scabies. The scabies rash can cover most of the body. Even a child’s palms, soles, and scalp can be infested with mites.
In babies, the rash often appears on the palms and soles. Babies who have scabies are very irritable and often do not want to eat or sleep. Children, too, are often very irritable. The itch can keep them awake at night.
Scabies rash on infant
Small, pus-filled bumps on the sole are often a sign of scabies in infants and young children.
Crusted scabies
Also called Norwegian scabies, crusted scabies is a severe form of scabies. People who have crusted scabies have 100s or even 1,000s of mites in their skin. By comparison, most people who get scabies have 15 to 20 mites on their skin.
Crusted scabies develops in people who have a weak immune system due to a medical condition, the elderly, and people who are living in institutions. Crusted scabies develops when the person’s body cannot develop any resistance to the mites. Without resistance, the mites quickly multiply.
A common sign of crusted scabies is widespread crusts on the skin. These crusts tend to be thick, crumble easily when touched, and look grayish in color. Sometimes the crusts appear on one or a few areas of the body such as the scalp, back, or feet.
Crusted scabies on arm and chest
Crusts, such as the one on this man’s arm and chest, form when people get crusted scabies, also called Norwegian scabies.
Images
References
Czelusta A, Yen-Moore A, Van der Straten M et al. An overview of sexually transmitted diseases. Part III. Sexually transmitted diseases in HIV-infected patients. J Am Acad Dermatol 2000; 43: 409-32; quiz 33-6.
Habif, Campbell, Chapman, et al. In: Dermatology DDxDeck. 2006. China. Mosby Elsevier. Card #92: Scabies.
Steen CJ, Carbonaro PA, Schwartz RA. Arthropods in dermatology. J Am Acad Dermatol 2004; 50: 819-42, quiz 42-4.