Pthirus pubis infestation

Pthirus pubis Infestation: A Description

Pthirus pubis, also known as crab lice or pubic lice, is a parasitic infestation that affects humans. The infestation is characterized by the presence of tiny insects, called lice, in coarse body hair, including pubic hair, armpit hair, beards, chest hair, eyelashes, and eyebrows.

Symptoms

The symptoms of Pthirus pubis infestation include:

• Intense itching in the genital area [8]
• Visible nits (lice eggs) or crawling lice on the affected hair shafts [2][5]
• Irritation and scratching in the affected areas [9]

Life Cycle

Pthirus pubis has a three-stage life cycle: egg, nymph, and adult. Females lay approximately 30 eggs during their 3-4 week lifespan, which are then attached to the hair shafts [1].

Transmission

The infestation is typically transmitted through skin-to-skin contact with an infected person or through direct contact with infested objects, such as toilet seats, sheets, and blankets [4][12].

Prevalence

Pthirus pubis infestations are relatively common, affecting 2-10% of human populations worldwide [11]. Outbreaks have been recorded in the past, but incomplete records preclude a definitive population cycle.

Key Facts

• Pthirus pubis is an obligate ectoparasite of humans, feeding exclusively on blood.
• The lice are tiny, wingless insects that live in coarse body hair.
• They can also infest other areas of the body covered with coarse hair, such as the perianal area and eyelashes.

Overall, Pthirus pubis infestation is a common health issue that requires awareness and understanding to prevent and treat effectively.

Diagnosing Pthirus pubis Infestation

Pthirus pubis, also known as pubic lice or crab lice, can be diagnosed through a visual examination of the affected area. Here are some diagnostic tests that may be used to confirm an infestation:

• Visual Examination: A healthcare provider will typically perform a thorough physical examination to look for signs of Pthirus pubis in the pubic area. This may involve using a magnifying glass or microscope to spot the lice.
• Magnifying Glass: A magnifying glass can be used to inspect the affected area for the presence of lice and nits (lice eggs).
• Microscopic Examination: In some cases, a healthcare provider may use a microscope to examine lice or nits removed from the eyelashes with forceps. This is typically done when there are symptoms of eye irritation.
• Tape Test: A piece of tape can be applied to the infected area to pick up lice to examine them under a microscope.

Self-Diagnosis

It's also possible for individuals to diagnose themselves by thoroughly examining their pubic area using a magnifying glass. However, this should not be relied upon as the sole means of diagnosis, and a healthcare provider should still be consulted if symptoms persist or worsen.

References:

• [1] A visual examination is typically ordered when a person has symptoms of a pubic lice infestation.
• [3] The presence of moving lice confirms a pubic lice infestation through a visual examination of the pubic area.
• [9] You can usually diagnose yourself by thoroughly examining your pubic area using a magnifying glass to look for pubic lice if you suspect an infestation.
• [11] Healthcare providers may use a magnifying glass to inspect the affected area for the presence of lice and nits.

Treatment Options for Pthirus pubis Infestation

Pthirus pubis, also known as pubic lice or crab lice, can be treated with various medications. The most common treatment options include:

• Permethrin: A 1% cream rinse applied to the affected area and washed off after 10 minutes is a recommended regimen for pediculosis pubis [5]. Permethrin is considered the drug of choice by most authorities as the first line of treatment in head, pubic, and severe body louse infestation [3].
• Ivermectin: Oral ivermectin has been used to treat Pthirus pubis infestations, with a regimen of 200 μg/kg/week for 2 successive weeks showing almost complete eradication of the infestation [6]. However, its use is not as common as permethrin.
• Pyrethrins and piperonyl butoxide: A mousse containing pyrethrins and piperonyl butoxide can also be used to treat Pthirus pubis infestations [2].
• Topical cream or shampoo: Your healthcare provider may prescribe a topical cream, shampoo, or oral medication to treat the infestation. Oral medicine works by killing the lice once they bite you [4].

Important Notes

• It's essential to carefully remove all lice and nits from the affected area for effective treatment.
• Treatment should be repeated in 7-10 days to ensure complete eradication of the infestation.
• In some cases, a combination of treatments may be necessary.

References:

[1] Pubic lice symptoms, diagnosis, treatment, and prevention (search result 1) [2] Nov 12, 2024 — Treatment options for pediculosis pubis (search result 2) [3] Permethrin as the drug of choice for treating Pthirus pubis infestations (search result 3) [4] Oral ivermectin treatment regimen for Pthirus pubis infestations (search result 6) [5] Recommended treatment regimen for pediculosis pubis (search result 5)

Differential Diagnosis of Pthirus pubis Infestation

Pthirus pubis, also known as the pubic louse or crab louse, is a parasitic insect that infests human hair. The differential diagnosis of Pthirus pubis infestation involves identifying other conditions that may present with similar symptoms.

Conditions to Consider:

• Seborrheic dermatitis: This condition presents with erythema and scaling on the scalp, eyebrows, nasolabial folds, and central chest [1]. While it can cause pruritus (severe itching), it is not typically associated with infestation.
• Acne necrotica: This condition presents with inflamed follicular papules and pustules, black crusts, and scarring. It may be confused with Pthirus pubis infestation due to the presence of crusting lesions [1].
• Phthiriasis palpebrarum: This is an ectoparasitosis of the eyelashes caused by an infestation with Pthirus pubis. It presents with itching, redness, and swelling around the eyes [3].
• Body lice: While not typically associated with hairy areas, body lice can be found in clothes and occasionally on the body. They are often confused with Pthirus pubis due to their similar appearance [10].

Key Differences:

• Location of infestation: Pthirus pubis infestations are typically confined to hairy areas, such as the pubic region, eyebrows, or scalp.
• Type of lesions: Pthirus pubis infestations often present with crusting lesions, whereas seborrheic dermatitis and acne necrotica may have different types of lesions [1].
• Transmission: Pthirus pubis is primarily transmitted through sexual contact or close personal contact with an infested individual.

References:

[1] Seborrheic dermatitis and acne necrotica are conditions that can present with similar symptoms to Pthirus pubis infestation. However, they have distinct differences in terms of location, type of lesions, and transmission. [3] Phthiriasis palpebrarum is an ectoparasitosis of the eyelashes caused by an infestation with Pthirus pubis. [10] Body lice are often confused with Pthirus pubis due to their similar appearance. However, they have distinct differences in terms of location and transmission.

It's essential to consider these conditions when diagnosing a Pthirus pubis infestation, as accurate diagnosis is crucial for effective treatment and management.