McKenzie Pediatrics 2008
What Is Scabies?
Scabies are little insects called mites that are invisible to the eye, and that burrow under the skin causing severe itching and little red bumps. They rarely attack the skin above the neck, except in children under age 2.
The mites can attack any other part of the body, especially places with lots of folds: the armpit, the creases opposite the elbow, the wrist, between the fingers & toes, the genitals, and behind knees. The waistband region, abdomen, and thighs are also favorite sites for scabies, while the back is seldom infested.
Scabies is NOT a poor person's disease. Scabies affects people from all income levels and walks of life. It is more likely to cause symptoms in children than in adults, but adults CAN get scabies, too!
What Are The Symptoms?
Scabies causes a red bumpy (and occasionally blistering) rash with moderate to severe itching, worse at night. The itch may begin before the rash ever appears.
Sometimes burrow are seen, appearing as white-grey threadlike lines within the skin where the insect has tunneled to take up residence. In children under age 2, little nodules may be seen, representing a vigorous immune response.
If the rash has been scratched enough, scratch lines may be noted. Secondary infection with staph or strep may occur, causing spreading redness, boils, and/or scabs.
How Is Scabies Spread?
The insect is spread person-to-person, or through the sharing of, or coming in close contact with, infested towels, bedding, pillows, or clothing. It does not live on hard surfaces such as countertops, faucet handles, door knobs, or toys. If cannot live away from the human body for more than 24 to 48 hours.
The time from contact to itch and then rash can range from 4 weeks to as long as 6 months. Therefore, it is often difficult to determine the source of infestation. If a child came in contact with the insect while not in the presence of her parents or siblings, she can spread the infestation to them but their symptoms may not appear until weeks or months after hers.
The infestation is contagious until it is treated with medication.
What Is Often Confused For Being Scabies?
It can be difficult even for physicians to diagnosis scabies. In its classic form, the scabies rash has an appearance most physicians have learned through experience to recognize. But not all scabies appear the same. There are tests - non-painful skin scrapings - that can be done to look for the insect, but many physicians do not have the necessary microscope to perform this test.
Scabies is often treated based on recognition of its rash, a recognition that can be mistaken. Resolution of the itch and (eventually) the rash confirms the diagnosis, as the treatment for scabies does not treat any other skin condition. If the itch and rash fail to improve, a second course of treatment may be prescribed, or another diagnosis may be considered.
Similar rashes include: other insect bites, eczema, contact dermatitis, impetigo, papular urticaria, seborrheic dermatitis, psoriasis, or a simple viral rash.
How Is Scabies Treated?
Treatment of choice is 5% permethrin, a plant-based chemical and natural insecticide and repellent. The most common form of permethrin is a cream, under the brand name Elimite.
The cream is applied at bedtime, from the neck down to the feet, covering every square inch of body surface (including the genitals, and between the fingers and toes). The cream is rinsed off in the morning, at least 8 hours after application. The treatment is repeated in exact 7 days.
It is recommended that all members of the household be treated with the cream the first night. Only the child with the rash needs treated a second time.
Beware that application of the cream does NOT immediately end the rash or the itch. It will take 3 to 6 weeks before both resolve. Contact your child's physician if after 6 weeks no improvement has been noted.
In the meantime, treat the itch with a night time dose of Benadryl™. This medication can be used every 6 hours, but can cause sleepiness, and thus is best avoided during the day. If the child is itchy during the day time, giving a morning dose Zyrtec™ can help alleviate the itch for up to 12 to 24 hours. If the itch returns by bedtime, it is okay to give the child a dose of Benadryl™. Use of generic forms of these medications is encouraged!
How Is Scabies Controlled?
Environmental decontamination is crucial to reducing or preventing spread of the mites. All of the child's bedding (sheets, blankets, comforters, and pillowcases), towels, and washcloths must be laundered in hot water, and dried on a high-heat setting. Also launder in hot water every item of clothing the child has recently worn, including pajamas.
Any fabric item that the child has come in contact (pillows, stuffed animals)with that cannot be laundered must be put into a plastic garbage bag for minimum of 72 hours. An upholstered couch or sofa that the child spends time on should be covered with plastic sheeting for a minimum of 72 hours.
When Is My Child No Longer Contagious?
The child may return to school or daycare the morning after her first treatment.