Scabies has been described by physicians for more than 2,000 years and was the first infection in humans for which a responsible organism was specifically identified. The cause of scabies is a tiny, eight-legged arthropod called a mite, which carries out its life cycle on and within human skin. Female mites (twice the size of males) are only about 3/10 of a millimeter long and barely visible to the naked eye. They cannot hop or fly, and thus transmission from one person to another nearly always involves skin-to-skin contact. The female mite burrows below the skin in a meandering pattern, laying a few eggs each day. After two to four weeks, she dies. Her eggs hatch, and new mite larvae grow, molt, and eventually emerge on the skin surface. The itching and rash of scabies don’t begin until 10 to 30 days after the first mites crawl under the skin, since itching is actually an allergic reaction to the mites, their eggs, and their waste products.
Scabies infections are more common in crowded living conditions where there is more opportunity for skin-to-skin transmission. They tend to be worse among those who cannot bathe very often, in which case hundreds or even thousands of mites may infest one individual. (Normally, fewer than 15 active mites are enough to cause symptoms.)
If your child or anyone in your family experiences intense itching, especially at night, you should suspect scabies. In older children, numerous itchy, fluid-filled bumps may be visible next to a reddish burrow track on the hands, feet, face, elbows, waist, wrists, and/or genitalia. In younger children, the bumps appear more often on the upper half of the body.
Unfortunately, burrow tracks aren’t always evident without a close look at certain areas (such as the spaces between the fingers or the toes). The severe itching provokes equally intense scratching, which may damage skin. This in turn may become infected by bacteria. As a result, scabies can look like nearly any other skin disease, a problem that could delay the correct diagnosis.
If your child’s doctor suspects scabies, he or she will examine the rash and may gently scrape the skin of the affected area to examine it for mites or eggs. If mites are found or if the rash is highly suspicious even when mites are not visible, one of the anti-scabies medications (usually permethrin or lindane) will be prescribed. The medication is usually a lotion. It must be applied to the en-tire body, left on for a number of hours, and then rinsed off. Your child should shower and tussle his body and hair completely when rinsing. Since scabies is so contagious, it is likely that your doctor will choose to treat everyone in your household so your child does not become re-infected.
It is important to follow your doctor’s directions precisely. Concerns have been raised about the possibility that lindane might cause seizures in children, and that this medication should be avoided in children with pre-existent epilepsy. It is also not recommended for use in infants and toddlers nor in pregnant women or nursing mothers. In addition to the anti-scabies medication, your doctor may prescribe anti-itch medication (such as cortisone cream or calamine lotion). Antibiotics may be needed if any areas of skin have become infected.
Once the first round of medication is applied, your child is no longer contagious. However, the rash will continue to be visible and itchy for up to four weeks. You should not repeatedly treat your child with anti scabies medication to stop the itching. If the itching does not go away after a month, it is possible that your child has be-come re-infected, but you should not use another round of medication until specifically told to do so by your child’s doctor.
Since scabies is transferred through close contact, it is important to treat anyone who leas had repeated direst contact with your child. In a few cases mites are spreading directly via clothing and linens, so wash these items is hot water after everyone has received the anti scabies medication.