What are they?

Crabs are related to head and body lice, but are found mostly in the pubic hair. Crabs live by feeding on human blood. They look like tiny crabs, one-two mm in diameter, grey in colour, and become brownish red when filled with blood. Crabs live for about 30 days and lay their eggs (“nits”) at the base of the hair. The average time it takes for the egg to hatch is eight-nine days, but they may lie dormant for 17 days. These eggs are very tiny but can be seen as whitish dots near the bases of the hairs. Crabs live for about 30 days and can survive 24–48 hours away from the human body.

Scabies are caused by mites that push under the skin to lay their eggs. These tiny mites are usually one-half millimetre in diameter. They are most commonly found between the fingers, around the genitals, on the wrists, buttocks, or under the arms. The female mite, when fertilized, burrows into the skin to lay eggs for a week and then dies. The eggs will hatch several days later and mature in about 10 days.

How are they spread?

Crabs and scabies are spread through close contact with an infected person. This may include, sexual contact, sharing infested bed linens, towels, clothing, and toilet seats. You have a 95 per cent chance of becoming infested after one contact with an infested person.

What are the symptoms?

You may not have symptoms of the crabs or scabies infestations for several weeks after contact. The first signs of crabs are usually itching in the genital or anal area. You may see the lice or their eggs, as well as bluish spots in the pubic area or thighs where crabs have bitten. Although crabs usually occur in the genital area, they may also be found in almost any body hair, such as in the armpits, on the chest, beard, eyelashes and head.

If you have scabies, you might get a rash on your armpits, thighs and waist, but they are most common between your fingers and toes. It is common to feel itching in these areas, especially at night, and after bathing and exercise.

How is it diagnosed?

You can usually tell if you have crabs by finding adult crabs or nits on the hairs. If it moves, it’s crabs. However, if you think you have scabies, you should be checked by a healthcare worker, as they are harder to recognize.

What are the complications?

There are no long-term complications associated with crabs or scabies; however, scratching infested areas can cause infection.

How is it treated?

The most common treatment for crabs and scabies is Kwellada, which can be purchased at any drugstore without a prescription. It is applied to infested areas after bathing. The cream or lotion is left on for eight hours (if you have bought the shampoo, only leave it on for four minutes), after which it should be washed off thoroughly. Crabs and nits on the eyelids can be removed with tweezers. Applying Vaseline to the edge of the lids helps kill the lice. Do not apply Kwellada or other pesticides to eye areas.

Infants and women who are breastfeeding or pregnant should not use Kwellada.

All clothing and linen used in the past week should be washed in hot water and/or dried in a hot cycle, or dry-cleaned. If you cannot wash quilts and blankets, they can be stored in sealed plastic bags for two-three weeks. Exposing crabs and scabies to freezing temperatures will kill them (you may want to put toys or blankets in the freezer if they cannot be washed).

Itching often continues for several days after effective treatment. Repeat treatment only if more crabs, nits or scabies burrows are found. If a second treatment is required, wait one week. Do not treat a third time—if the infestations continue after two treatments, see your healthcare worker.

What about sexual partners?

Inform all sexual partners of the past month. Remember that all members of your household and anyone else that have had close contact with you (not necessarily sexual) should also be informed, examined and treated.

Prevention

Avoid close contact and sexual activity until you and your partner(s) no longer have crabs, nits, or scabies, and all clothing, bed linens etc. have been cleaned.