Pubic Lice & Scabies: 2 Annoying and Intensely Itchy STIs

Both pubic lice (crabs) and scabies are parasitic STIs. Tiny lice is the parasite responsible for pubic lice while mites dwelling and burrowing under the genital area are the culprit behind scabies. Although pubic lice and scabies can be easily treated, these parasitic infestations are, to say the least, bothersome. One interesting fact about scabies and pubic lice is that the regular use of condoms does not prevent the spread of these STIs. These sexually-transmitted infections are a result of close physical contact and sexual activities act as the main and most common way of transmission. Not limited to sexual activities, the two STIs can spread by sharing bed sheets, towels or clothes with an infected person. However, since these parasites can only live on for 24 to 48 hours outside their hosts (human body), getting infected from a toilet seat is pretty unlikely.

Pubic lice

Pubic lice are often referred to as ‘crabs’ due to their appearance that resembles crabs.  Sometimes, lice can also be found in other parts of the body with coarse hair such as underarms, legs, and face. Very rarely, lice are found in eyebrows and eyelashes. According to the Centers for Disease Control and Prevention (CDC), these lice are typically 1.1-1.8mm in size. You can see these lice and the eggs with naked eye. It is important to note that pubic lice is different from head lice.

One obvious symptom of pubic lice is intense itchiness around the genital area. Pubic lice thrive off human blood and itchiness is caused by their bites. This itchiness is more severe at night. Pubic lice can easily be diagnosed. Health professionals can tell whether or not a person has pubic lice through visual examinations. A magnifying glass might be used to detect the eggs. As mentioned above, pubic lice is relatively easy to treat as it can be relieved by over-the-counter treatment. Over-the-counter lotions and creams also terminate the parasites and eggs. People with other sexually-transmitted infections are more likely to get pubic lice. Although untreated pubic lice usually does not lead to serious complications, several conditions that may arise from it are:

  • Discoloration. Muted blue spots may emerge on the spots where the lice continuously feed off blood.
  • Secondary infections. Since lice bites can be terribly itchy, this might prompt people to scratch themselves. These scratches can cause wounds and lead to infections.
  • Irritations on the eyes. Children with pubic lice on the eyelashes can end up having conjunctivitis.
  • Pubic lice prevention includes not engaging in sexual contact or sharing clothing, bedding and towels with an infected person. Sexual partners of a person who is being treated for pubic lice should also receive treatment.


Sarcoptes scabiei is around 0.5mm in length and the cause behind scabies. A parasitic mite found in all parts of the world, Sarcoptes scabiei burrows into and lays their eggs under human’s skin. According to the CDC, scabies can affect every race and social class and some places where infestations are rife include childcare facilities, nursing homes and prisons. Sometimes, scabies can be mistaken for pubic lice because both STIs result in extreme itchiness. One obvious difference, however, is the fact that these mites cannot be seen by the naked eye due to their tiny size. Mites will make new burrows everytime the eggs hatch.

Similar to how pubic lice is transmitted, the spread of scabies is done through close physical contact. Sexual activities, direct skin-to-skin contact (can be non-sexual) and making contact with clothing, bedding and towels of an infected person is how people can be exposed to this STI. One crucial thing to remember is that the transmission of scabies usually involves direct and prolonged skin-to-skin contact with an infected person. Direct but short contact such as a handshake or hug normally does not spread scabies. This is why scabies can be transmitted rather easily between sexual partners or among family members. Scabies is highly contagious and the incubation period can range between 4 to 6 weeks (for first-time infections). An infested person can still spread scabies even when symptoms have not appeared. However, people who get reinfected may develop symptoms within a few days (1-4 days).

Intense itchiness that occurs at night or after taking a shower or bath is one symptom of scabies along with pimple-like rash which are red and raised. In some cases, the rash and itchiness can affect most of the body, but sometimes they may only occur in common body parts such as the elbow, armpit, buttocks, nipples, and wrist. Secondary infections due to scratching may also take place as it causes skin sores. These sores can later get infected by bacteria. Some people can have burrow markings taking the form of grayish or silvery lines on the skin surface. These markings are a result of female mites burrowing under the skin.

Diagnosing scabies is done through visual inspections. Usually, healthcare professionals will check the distribution of the rash and whether or not burrow markings are present. If possible, they will also examine the kinds of mites by removing a mite from the burrow’s end with a needle to be observed under a microscope. Scabies can survive up to 2 months in a person. But, since these mites are parasitic and need a host to live on, they cannot survive more than 72 hours off a person.

Although not particularly dangerous, scabies still need to be treated. The treatment for this STI is called scabicides which takes the form of creams or lotions. These lotions will put an end to the mites and their eggs. No over-the-counter treatments are available for scabies. As with pubic lice, sexual partners of an infected person should also be treated for the disease.

Visit Your STD Clinic

Practicing safer sex and limiting the number of sexual partners are two ways we can protect ourselves from STDs. However, getting regularly tested is equally important. Shim Clinic is a STD clinic Singapore. We provide STD testing, diagnosis and treatment of diagnosed STDs. We also carry prevention methods such as HIV PEP, HIV PrEP, and HPV vaccination (Gardasil-9).