Parasitic Infections: Scabies & Public Lice

Sexually Transmitted Infections: Parasitic Infections – Scabies & Pubic Lice

This article mainly highlights both Scabies and Pubic Lice as other types of STIs. Further discussion on both individual parasites may be shared in more detail in other articles. 

Scabies Infection

Scabies infection is caused by parasite Sarcoptes scabiei. In adult, Scabies is often transmitted through sexual contact. This is not the case in children with scabies.

When a person is infected with Sarcoptes scabiei parasite, it takes a few weeks for the body to be sensitized towards it, then only one will experience the classical symptoms of intense itch. Interestingly, in subsequent re-infestation of Scabies, one can develop itch symptoms within 24hours. This is because the body has already been sensitized by the Scabies parasite. 

What are the Symptoms and Signs of Scabies?

  • Intense itch
  • Scabies rash
  • This occur anywhere on the body except the head but typically occurs over the web spaces of fingers and toes, groin and genital region
  • Silvery linings, trail-like lines also known as burrows can be seen occasionally
  • Scabies rash typically are confused with eczema which does not go away

People with poor immune systems, elderly or the young can acquire scabies rash affecting the head. This is termed Crusted Scabies also known as Norwegian Scabies. 

What are the Treatment Options for Scabies Infections?

  • Permethrin 5% cream
  • Applied to all areas of the body from neck down, leave on and only washed off after 8-14 hours.
  • Repeat treatment 1 week later
  • Oral Ivermectin 200mg/kg
  • Repeat another dose 2 weeks later

 Speak to your doctor if you have a poor immune system or other medical conditions such as HIV that may place you at risk of developing widespread Scabies, known as Crusted Scabies. 

  • You should wash all your clothing, bedding, linen at 50C or higher.
  • Clothing that is not able to be washed should be placed in sealed bags for 3 days until the scabies mites die.
  • Keep your fingernails short and trimmed, to avoid skin infection due to excessive scratching.
  • Your sexual partner, close personal, household members within 1 month preceding scabies infestation should be treated.
  • Abstain from sex until you and your partners have been treated.
  • You should be screened for other STIs including HIV.

Why Should I treat Scabies?

Apart from the discussed discomfort symptoms from Scabies, Scabies can cause outbreaks in Institutional settings such as residential places, nursing homes, hospitals. It is important to prevent and contain the infectious Scabies infection before it turns into an epidemic by treating the affected population. 

Pubic Lice Infection

Pubic Lice also medically termed pediculosis pubis or also colloquially known as ‘crabs’ are tiny parasites that thrive on pubic hair.

The lice can also be found in other areas such as

  • Eyelashes or eyebrows
  • Facial hair in particularly beards and moustaches
  • In between hair of the chest, abdomen, and back
  • Armpit hair
  • Leg hair
  • Interestingly pubic lice are not found on the scalp hair (Head lice do though!)

Pubic lice can be spread by sexual contact by close body contact with an infected person. It is unrelated to poor personal hygiene. Pubic lice crawl from hair to hair, but they are not able to fly or jump. They feed on human blood for survival. 

What are the Symptoms and Signs of Pubic Lice?

  • Itch, worse at night
  • Red, inflamed and irritated skin due to scratching
  • Black powder found on your underpants
  • Small blue or red spots on your skin due to bite marks

What are the Treatment Options for Pubic Lice?

  • Permethrin 1% cream. Applied to the affected area and washed off after 10 min. Repeat treatment 1 week later
  • Malathion 0.5% lotion. Applied to the affected area and washed off after 8-12 hours. Repeat treatment 1 week later
  • Oral Ivermectin 250mg/kg. Repeat another dose 2 weeks later
  • Eyelashes with pubic lice should be treated with the application of occlusive petroleum jelly or ophthalmic ointment to the affected area twice a day for 10 days.
  • Wash all clothing, towels and bedding in a washing machine on a hot cycle 50C or higher to ensure all lice are killed.
  • Sexual partners within the previous month should be treated.
  • Abstain from sexual contact until clearance.
  • You should be screened for other STIs including HIV.

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