# Pediculosis and Ectoparasitic Infestations

> Pediculosis and ectoparasitic infestations for NEET-PG Medicine: head, body and pubic lice, myiasis, tungiasis, and permethrin and ivermectin treatment.

- Canonical URL: https://prepelephant.com/topics/neet-pg/medicine/pediculosis-and-ectoparasitic-infestations
- Exam / course: NEET-PG · Subject: Medicine
- Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team
- First published: 2026-10-14
- Last updated: 2026-10-14
- Reference basis: Rook's Textbook of Dermatology; IADVL Textbook of Dermatology; Harrison's Principles of Internal Medicine
- How to cite: "Pediculosis and Ectoparasitic Infestations", PrepElephant, https://prepelephant.com/topics/neet-pg/medicine/pediculosis-and-ectoparasitic-infestations

## Direct answer

Pediculosis is infestation by human lice, with head, body and pubic lice each transmitted differently and treated with a topical pediculicide. Body lice are the vectors of epidemic typhus, trench fever and relapsing fever, while head and pubic lice cause itch without systemic disease. Permethrin is the first-line topical agent for head lice, pubic lice and scabies, and oral ivermectin is an alternative in selected cases.

## What you must remember

- **Head lice:** Pediculus humanus capitis glues its nits to the hair shaft near the scalp, and itch with visible nits is the main clue.
- **Body lice:** Pediculus humanus humanus lives in clothing seams rather than on the skin, and it transmits epidemic typhus, trench fever and relapsing fever.
- **Pubic lice:** Pthirus pubis infests pubic hair and sometimes the eyelashes, and it is spread by close sexual contact.
- **Permethrin:** a pyrethroid topical insecticide that is first-line for head lice, pubic lice and scabies, with resistance reported in head lice.
- **Myiasis:** fly larvae infest tissue, and furuncular myiasis presents as a boil with a central breathing pore.
- **Tungiasis:** the female sand flea Tunga penetrans burrows into the feet, often under the toenails, and is removed with sterile technique.
- **Scabies:** Sarcoptes scabiei burrows into the skin, and all household contacts are treated together.

## Matching the infestation to the treatment

Ectoparasites differ in where they live, and the site often predicts the treatment. Some of them are also vectors, which changes both the public health response and the urgency. The table lists the infestations most likely to appear in an exam stem.

| Infestation | Parasite | Site | Key treatment |
| --- | --- | --- | --- |
| Head lice | Pediculus humanus capitis | Scalp and hair shaft | Permethrin lotion or dimeticone, with nit combing |
| Body lice | Pediculus humanus humanus | Clothing seams | Treat the person and decontaminate clothing |
| Pubic lice | Pthirus pubis | Pubic hair, eyelashes | Permethrin lotion, with partners treated |
| Scabies | Sarcoptes scabiei | Burrows in the skin | Permethrin, or oral ivermectin in selected cases |
| Tungiasis | Tunga penetrans | Feet, toes and nails | Surgical removal under sterile technique |

Body lice need clothing decontamination as well as treatment of the person, because the parasite lives in seams rather than on the skin. Scabies and pubic lice both need the sexual or household contacts treated at the same time, since reinfection is common otherwise.

## Traps in ectoparasite stems

Most lost marks come from choosing a systemic drug for a topical problem or forgetting the vector role of body lice.

- **Trap:** a child with nits in the hair is given an oral antiparasitic first. **Correct:** head lice are treated with a topical pediculicide such as permethrin or dimeticone, and nit combing removes the eggs.
- **Trap:** body lice are treated on the skin only, and the patient is reinfested. **Correct:** clothing and bedding must be decontaminated as well, because the lice live in the seams.
- **Trap:** a boil with a central breathing pore is treated with antibiotics alone. **Correct:** furuncular myiasis is a larval infestation, so the pore is occluded to bring the larva out and the larva is then extracted.

## Frequently asked questions

### Which lice transmit epidemic typhus and relapsing fever?

Body lice, Pediculus humanus humanus, transmit epidemic typhus, trench fever and relapsing fever. Head and pubic lice do not carry these vector-borne diseases, which is why body lice matter in epidemics and crowded settings.

### What is the first-line treatment for head lice?

Topical permethrin lotion is the first-line treatment for head lice, with dimeticone and malathion as alternatives. Nit combing removes eggs, and the scalp is treated again after the interval given in the product guidance.

### Which mite causes scabies and how is it treated?

Sarcoptes scabiei, a mite, burrows into the skin to cause scabies. Permethrin cream is first-line, with oral ivermectin used in selected cases, and household contacts are treated at the same time.

### What is furuncular myiasis and how is the larva removed?

Furuncular myiasis is a boil-like skin lesion containing a fly larva, usually with a central breathing pore. The pore is occluded so that the larva surfaces, and then the larva is extracted with forceps.

### How does tungiasis differ from scabies in its site of disease?

Tungiasis is caused by the sand flea Tunga penetrans, which burrows into the feet, often under the nails. Scabies is caused by a mite that burrows mainly in finger webs, wrists and skin folds, and it is treated with antiparasitic creams or oral drugs.