Things To Know About Crab Lice

Lice feed on human blood. There are three types: head lice, which are common in children; clothing lice – sometimes called body lice – which are common in vagrants, live in clothing and only visit the skin to feed; and crab or pubic lice.

How crab lice (pubic lice) are caught

Lice cannot jump, hop, fly or swim. Crab lice probably cannot be caught from lavatory seats or even from bedclothes, but this is not 100% certain. They probably cannot survive for more than 24 hours away from a person. They are transmitted by close body contact, during which they are able to transfer their grip from one person’s hair to that of the other before letting go entirely from the first person. Sexual contact is their ideal situation.

Where crab lice live

Crab lice cannot live in hair that is too dense, so they will not colonize the hair of the scalp (except at the hairline). However, they will live happily on armpit hair, eyebrows, eyelashes, chest hair and upper thigh hair as well as pubic hair.

How to tell if you have crab lice

Itching occurs, especially at night, in the pubic hair area.

Seeing the lice. The lice are small (up to 2 mm long), and can just be seen with the naked eye. They are squat in shape and, with a magnifier, you can see that all the legs emerge close together from the front of the body, and the middle and hind legs have large pincer-like claws giving the ‘crab’ appearance. They use their claws to grasp hairs close to the skin surface. They hardly move except at night, when they slowly transfer their grip from one hair to another.

 

Nits, which are the egg cases, can be seen attached to the hairs. The female lays the eggs in a hard brown shell, which she attaches to the hair on the surface of the skin. As the hair grows, the egg case will be further up its shaft, so the position of the nits on the hair gives you an idea of how long you have had them. After about 8 days the eggs hatch, and the empty egg case appears white and is easier to see.

 

Rust-coloured specks may be seen on the skin – these are louse faeces.

 

Blood specks may be seen on underwear.

What you can do about crab lice

There is a choice of treatment for crab lice (pubic lice). In the UK, you can buy insecticide lotions to kill crab lice from pharmacies, without a prescription. Some contain alcohol, which can irritate the skin of the scrotum and any scratched areas, so a lotion that does not contain alcohol is preferable - check the label for information.
A single application of the lotion is probably enough, but some specialists advise another application after 7 days to eliminate any newly hatched lice. Apply the lotion to the whole body from the neck down, even if you think only the pubic area is affected. A paintbrush is the best method. To be on the safe side, change underclothes and bedlinen after treatment.

Do not treat yourself, but go to a doctor, if:

• you are pregnant
• you think you have crabs on your eyelashes or eyebrows; do not try and treat these yourself with lotion.

A survey revealed that 80% of students think that antibiotic creams or tablets will get rid of pubic crab lice. This is completely wrong; antibiotics do not affect lice at all.

What your doctor can do

You can see your family doctor or go to a genitourinary medicine clinic. The advantage of the clinic is that the staff are expert crab spotters who will be able to confirm that your diagnosis is correct. Also, you can have tests to check you have not picked up any other infection at the same time, and the treatment will probably be free.