Pubic Lice, Pubic Crab, Pediculosis and Pthiriasis

Do you have a persistent genital itch or discomfort that does not seem to be going away despite repeated visits to your doctor? Is your partner feeling itchy as well?

You may want to consider broadening your differentials to include parasites that may be thriving and crawling around your genital region. Pubic lice infestation affects between 2 to 10 percent of the human population with outbreaks from as far back as the 1970s.

In this article, we will dive into the unpleasantries of pubic lice. As scary as it sounds, pubic lice can be treated. Do read on.

What are pubic lice?

Pubic lice, also known as “pubic crab”, are considered parasite infestations that can happen in your genital region.

Pubic lice can appear in 3 stages, these are:

• Stage 1, Nit: These are the eggs of the lice. They are whitish to yellowish round bumps that are usually stuck onto the hair shaft. It takes 6-10 days for the nits to hatch into louse.
• Stage 2, Nymph: Once the louse is hatched from the nit, they have to feed on blood. It takes another 2 to 3 weeks for the small louse to grow into an adult pubic louse.
• Stage 3, Adult: Under a microscope, adult pubic louse is crab-like in appearance with 6 legs; the 2 fore legs are bigger, similar to the pincer claws of a crab. Adult pubic lice 1.1 to 1.8 mm in length.

How common is pubic lice in Singapore?

Regardless of your gender, ethnicity, race or socioeconomical standing, pubic lice infestation can affect anyone in Singapore.

Adult Singaporeans commonly infect one another with pubic lice through sexual contact, however, it can spread through close personal contact such as sharing clothing, towels, and linen from someone infected with pubic lice.
If there is pubic lice infestation on a child, especially if seen on their head or eye lashes, this can suggest the possibility of sexual abuse. Although, they could have simply contracted it by sharing clothing, bedding or towels with someone infected with pubic lice.

Where can I find pubic lice?

Pubic lice can be found in your genital region. It is possible to pick out lice in areas of your body where coarse hair is present such as your armpit, beard, eyebrow, eye lashes, legs, or body. If you notice lice on your head, it is most likely due to head lice as opposed to pubic lice.

What are the risk factors of being infected by pubic lice?

Pubic lice are unable to fly or jump, but can climb from the hairs of one person to another. This increases the risk of being infected with pubic lice through the following factors:

• Being sexually active
• Having more than 1 sexual partner in a period of time
• Engaging in sexual activities with someone infected by pubic lice
• Sharing clothing, towels, or bedding with someone infected by pubic lice

What are the signs and symptoms of pubic lice?

Signs and symptoms to look out for if you suspect you have been infected by pubic lice include:

• Itching in your genital region is usually the main symptom of pubic lice
• Small red bumps on your skin due to bites from the lice. Overtime, these bumps can turn into small blue spots
• The appearance of small dark red faeces on your skin
• Visible nits and lice on and/or near your pubic region

How are pubic lice diagnosed?

Pubic lice are diagnosed by physically pinpointing out louse or nits on the hair in the affected region — your pubic region or other parts of your body. Sometimes a magnifying glass or dermatoscope may be used for a better view of the lice or nits.

What should I expect when visiting my doctor concerning pubic lice?

During your doctor’s visit, your doctor will inspect areas of your body with hair. These areas include your genital region, body, armpit, eye lashes, eyebrows, and even scalp to fully screen the possibility of nits and lice. A comb and magnifying glass may be used to facilitate the visualisation of the lice in these areas.

Are pubic lice a Sexually Transmitted Disease (STD)?

Although passed on in a similar manner (through close contact and sexual intercourse), pubic lice are not considered a Sexually Transmitted Disease, but rather, they are a Sexually Transmitted Infection (STI). 

When a visit to your doctor’s office concerns pubic lice, you will most likely be advised to get screened for other types of sexually transmitted diseases and/or genital infections depending on individual risk factors. Your sexual partner will most likely be advised to get the same screening to reduce these risks.

What is the treatment for pubic lice in Singapore?

Thankfully, there is a cure for pubic lice and you do not have to live with this infestation.

Medication in the form of lotions, creams, or shampoos containing malathion, permethrin, pyrethrins or piperonyl butoxide can be used to kill pubic lice. You will be advised to apply the medication on your whole body to fully treat the infestation. This will need to be left on for 24 hours before washing off. You are required to repeat this cycle for a whole week (7 days) to ensure all pubic lice and nits are killed.

For any lice or nits that have made it onto your eyebrows or eye lashes, you will be advised to apply petroleum ointment onto your eyelids for 10 days as an additional treatment.

It is important that your sexual partner(s) also receive treatment to reduce their risk of a cross-infection; even if they are asymptomatic.

What should I do after pubic lice treatment?

1. Wash all clothing, towels and bedding in hot water (> 50℃). These should then be dry cleaned and placed in plastic bags for at least 2 weeks to ensure all lice are dead.
2. Mattresses should be vacuumed and cleaned to eliminate the presence of lice.
3. Avoid sharing personal items including combs, razor blades, tweezers, clothing, bedding, or towels moving forward.
4. If you had more than 1 sexual partner within the past month, they should be traced and informed for screening and treatment of pubic lice. Additionally, they can be screened for the possibility of other sexually transmitted infections.
5. Avoid sexual contact with others until the end of your pubic lice treatment.
6. Protect yourself against pubic lice by avoiding close or sexual contact with anyone you know that is infected with pubic lice until they have sought and completed the right treatment.

It is important to know that contraception methods such as barrier contraception are not effective at preventing pubic lice infections.

Can I contract pubic lice by sitting on dirty toilet seats or a couch?

Although it is possible for pubic lice to survive 1 to 2 days without human tissue cells, they generally do not fall off from their hosts unless the host themselves die.

Therefore, it is not possible to contract pubic lice from dirty toilet seats or a couch. This is because pubic lice rely on human tissue cells for survival and they will not be able to stay alive on other surfaces for long without live cells.

Pubic lice also do not posses the abilities to fly or jump, only climb from one person to another through close or sexual contact.