Pubic lice (crabs) and scabies

What are they?

Pubic lice (crabs) are tiny insects that nest in pubic hair and live by feeding on human blood.  Although crabs usually occur around the genitals and anus, they may also be found in any hairy part such as the chest, armpits, beard, eyelashes and, rarely, the head.  

They look like tiny crabs, one to two millimetres in diameter, grey in colour and become brownish red when filled with blood.  Crabs lay their eggs (“nits”) at the base of the hair.  These eggs are very tiny but can be seen as whitish dots near the base of the hairs.  Crabs live for about 30 days and can survive 24 to 48 hours away from the human body.

Scabies are caused by mites that burrow below the skin surface to lay their eggs.  These tiny mites are usually half a millimetre in diameter and are most commonly found in the folds of skin on the elbows, between the fingers, around the genitals, on the wrists, buttocks, breasts, penis, or under the arms.  The eggs will hatch several days later and mature in about 10 days.

How are they spread?

Crabs are usually spread through sexual contact. Scabies is spread by direct, prolonged, skin-to-skin contact with a person already infested with scabies. Infestation is easily spread to sexual partners and household members. Infestation may also occur by sharing clothing, towels and bedding as crabs and scabies can live on them for up to three days.

What are the symptoms?

The first sign of crabs is usually itching in the genital or anal area.  You may see the crabs, their eggs, or bluish spots where they have bitten you.

Signs and symptoms of scabies infestation are pimple-like irritations, burrows or rash of the skin (especially the webbing between the fingers; the skin folds on the wrist, elbow or knee; the penis, the breast or shoulder blades) and intense itching especially at night and over most of the body.

How are they 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 provider, as scabies are harder to recognize.

What are the complications?

There are no complications associated with crabs or scabies; however, scratching can lead to a skin infection.

How are they treated?

A permethrin or pyrethrin lice shampoo is recommended to treat crabs. These products are available at any drugstore without a prescription. Always follow the directions on the package insert. These medications should not be used near the eyes.

Wash the infested area; towel dry. Thoroughly saturate hair with lice medication and leave the medication on for 10 minutes. Thoroughly rinse off the medication with water. Dry off with a clean towel. Put on clean underwear and clothing after treatment. Re-treat in seven to 10 days if lice are still found.

Permethrin lotion is considered to be the most efficient scabies medication at present. Always follow the directions on the package insert. Apply lotion to a clean body from the neck down to the toes and leave overnight (10 hours). After 10 hours, take a bath or shower to wash off the lotion. Put on clean clothes.

A second treatment of the body with the same lotion may be necessary seven to 10 days later. Itching may continue for two to three weeks and does not mean that you are still infested. Your healthcare provider may prescribe additional medication to relieve itching if it is severe.

All clothes , bedding and towels used by the infested person two days before treatment should be washed in hot water (50 °C) and dried in a hot dryer (for at least 20 minutes), or dry cleaned. If you cannot wash quilts and blankets, they can be stored in sealed plastic bags for one week and then washed normally. Exposing crabs and scabies to freezing temperatures will kill them so you may want to put toys or blankets in the freezer if they cannot be washed.

What about sexual partners?

All household contacts and recent sexual partners within the past month should be treated to prevent re-infestation. 

Prevention

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