Scabies is a skin infection caused by mites. It is characterized by tracks of small itchy bumps or blisters made by mites burrowing into the skin. In children and adults, the lesions usually appear in the following areas:
- Between the fingers and toes
- On the inside of the wrists and elbows
- In the armpits
- Around the waist
- On the genitals, buttocks and nipples
In children younger than age 2, lesions may also be found on the head, face, neck, chest, back, palms of the hands and soles of the feet.
While scabies can be unpleasant, the presence of mites under the skin is not harmful in and of itself. However, lesions can become infected with bacteria if scratching leads to open sores. It is therefore important to treat the problem promptly, and to limit itching.
Causes and triggers
Scabies is usually spread through prolonged skin-to-skin contact with an infected person or, more rarely, with their personal items (e.g., clothing or bedding). Contrary to popular belief, mites do not jump or fly, and animals do not spread human scabies.
Once on the host's skin, mites burrow just beneath its surface where they make tiny tunnels in which they deposit their eggs. When the eggs hatch, the larvae work their way to the surface of the skin to reproduce and, in turn, burrow into the skin. This is what causes the visible track-like burrows on the skin.
As for the itching, it is caused by the body's reaction to the mites themselves, as well as their saliva, and excrement.
After the initial infection, it can take up to 6 weeks for symptoms to appear. That said, if a family member is infected, all household members should be treated, even if they show no signs of infection.
In most cases, your health professional will recommend a 5% permethrin cream or lotion as treatment:
- Apply product over the entire body, including the face in children younger than age 2.
- Leave on for 10 hours then rince off in the shower.
- Some treatments require a second application one week later to ensure that all the mites are killed.
Depending on your medical history and symptoms, your health professional may opt for another type of cream, or may even prescribe an oral medication.
Itching may persist for a few weeks after completing treatment even once the infection is gone. For some added relief from itching, cold compresses and a soothing lotion can be applied on the affected areas. If relief is still not achieved, your health provider may suggest a product to soothe the itching.
Mites can live for up to 3 days on objects that have been in contact with an infected person. To prevent reinfection, take the following precautions:
- Wash all clothing used in the 4 days before the infected person started treatment.
- Wash bedding and towels used by all household members.
- Dry everything that was washed in the dryer at the hottest setting.
- Store clothing or items that cannot be washed in hot water in an airtight plastic bag for 3 to 5 days, or bring to the dry cleaner.
- Vacuum the house and car then dispose of the vacuum bag.
When should I see a medical professional?
- If you or a family member have symptoms of scabies.
- If the skin is red, hot, tender, crusty, or oozing a yellowish liquid.
- If new lesions appear after treatment.