What is Phthiriasis Palpebrarum?
Phthiriasis palpebrarum, also known as phthiriasis ciliaris or ciliary phthiriasis, is a condition where the eyelashes are infested with the Pthirus pubis (sometimes spelled Phthirus pubis). This creature is also referred to as the pubic louse or crab louse. Phthiriasis palpebrarum is a blood-feeding insect that belongs to the Pediculidae family and Phthirus genus.
This condition is unusual and can often be confused with blepharitis, which is inflammation of the eyelid. It’s more commonly found in places with lower socio-economic conditions and may be more prevalent than previously reported. This is because its symptoms are similar to anterior blepharitis, which affects the front of the eyelid, leading to missed diagnoses. Also, the eggs (nits) and adult lice can easily be overlooked since they reside in the eyelashes of the eye.
The condition can cause symptoms like severe itching, redness in the eyelid (lid hyperemia), and scratched or irritated skin (excoriated skin). If Phthiriasis palpebrarum is found in a particular area, it suggests inadequate hygiene, overcrowding, poverty, and a lower socioeconomic environment. Policymakers should consider this significant infectious disease when creating and defining treatment guidelines.
What Causes Phthiriasis Palpebrarum?
Phthiriasis palpebrarum is an insect infestation caused by a type of lice known as Pthirus pubis, or crab louse. The adult crab louse is about 2 millimeters long, and it’s smaller than head and body lice. The males are generally smaller than the females. These lice have a rounded body with big claws on their rear legs which allows them to hold onto hair.
Crab lice primarily infest pubic hair (causing a condition known as phthiriasis pubis). But they can also spread to other hairy areas of the body like the stomach, thighs, chest, underarms, beard, eyebrows, and eyelashes. Crab lice need to feed on human blood multiple times a day to survive, and they can’t live longer than one to two days away from a human host. Female lice lay around three eggs daily, which then hatch in about a week to ten days.
Getting crab lice usually happens through sexual contact or close contact between a parent who has lice and their child. You can also get crab lice in your eyelashes by touching infested body hair or through sexual contact. Catching crab lice from clothes or towels with eggs on them isn’t as common, and some experts say it’s not possible. Sometimes, an infestation of crab lice in the eyelashes can be mistaken for an eye inflammation called blepharoconjunctivitis.
There have been reports of cases of crab lice infesting the eyelids. One notable case involved a 48-year-old woman who had both crab lice and another type of mite, Demodex, in her eyelids. Another documented case involved a young child getting crab lice in one eye while being treated for a vision condition known as amblyopia.
Risk Factors and Frequency for Phthiriasis Palpebrarum
Pubic lice affect around 1 to 2% of people worldwide. However, the exact number of people affected by eye lice (phthiriasis palpebrarum) is not known. As for body lice (phthiriasis pubis), studies suggest that between 2% and more than 10% of people have it. This figure might actually be lower than the real number, because many people might not report it to their doctor. In India, the numbers are especially likely to be underreported due to societal norms and stigma.
Eye lice are more commonly seen in children. Additionally, about 30% of lice cases are grouped under sexually transmitted diseases. Lice can also affect infants as young as 21 days old.
- 1 to 2% of the global population are estimated to have pubic lice.
- The exact number of people affected by Eye lice is unknown.
- Studies suggest that 2% to more than 10% of people have body lice.
- Many cases of lice may not be reported, especially in societies with social barriers and stigmas like in India.
- Eye lice are mostly diagnosed in children.
- About 30% of lice cases are sexually transmitted.
- Lice can even affect infants as young as 21 days old.
Signs and Symptoms of Phthiriasis Palpebrarum
Phthiriasis palpebrarum, a condition causing eyelid itching, can be challenging to diagnose due to the small and clear nature of the parasite and its eggs. This makes them virtually invisible. Symptoms can develop for several months before a correct diagnosis is made. Key symptoms include persistent scratching, rubbing of the eyelashes, general discomfort, and inflammation. Other less frequent signs include:
- A gritty feeling
- Redness of the eyes
- Swollen eyelids
- Reddish-brown crusts on the lids
- Watery eyes
- White discharge
- Burning sensation
- Irritation and pain
Additionally, itching in other hair-covered areas of the body could potentially indicate an associated condition, phthiriasis pubis. In rare cases, an eyelid abscess may develop.
A detailed examination using a slit lamp could reveal the translucent eggs, appearing as oval structures emerging from the base of the eyelashes. The moving and semi-transparent lice may be visible, their count, however, varies. Other signs like eyelid redness or swelling, eye redness, bloody crusts, and speckles of the eyelid skin due to the parasite feeding on blood are often observed. The parasite’s fecal material may appear as tiny brown granules. Generally, both eyes are affected by phthiriasis palpebrarum, with unilateral eye involvement being less common. The upper eyelids are typically affected the most. The condition generally does not affect visual acuity. However, pre-auricular lymphadenopathy, or swelling of nodes near the ear, may be noted, especially in cases of secondary bacterial infection at the site of scratching or parasite bites.
Testing for Phthiriasis Palpebrarum
When doctors suspect that a patient might be suffering from a parasitic infestation, such as lice, they may use several techniques to confirm their suspicion.
One common technique is to use a light microscope to directly examine a sample taken from the patient’s eyelids. This sample can be viewed through a light microscope at a ten times magnification or a special device called a ‘wood lamp’. The presence of lice and their eggs, known as nits, can usually confirm the infestation. This process also helps to identify the specific type of louse responsible for the infestation, such as ‘Pthirus pubis’.
An alternative examination technique is ‘dermoscopy’. This method involves studying the skin up close using a special microscope called a dermatoscope. It is a safe and definitive way to confirm louse infestation without causing any physical damage to the patient’s skin.
Lastly, in certain cases, such as during forensic investigations related to sexual trauma or abuse, the DNA of an individual (the host) can be identified from the blood inside the louse. This is achieved by using a technique called polymerase chain reaction (or PCR), which makes multiple copies of specific DNA segments for detailed study.
Treatment Options for Phthiriasis Palpebrarum
When it comes to dealing with lice on the eyelashes, the methods used can be pretty extreme. One method is to physically remove the lice and nits (which are lice eggs) by using a tool called a forceps. But, this can be challenging, especially with children who may find the process uncomfortable. An alternative option can be a substance called botulinum toxin A (diluted to a concentration of 2.5 units per 0.1 ml). This toxin, applied with a swab stick on the eyelashes, helps to paralyze the lice, preventing them from sticking to the eyelashes and making them easier to remove.
A range of topical (applied to the skin) medications can be used to treat lice on the eyelashes. These include things like 1% yellow mercuric oxide ophthalmic ointment and 0.3% tobramycin eye ointment, among others, all of which have been found to be effective against lice and nits. Additionally, there are over-the-counter treatments that kill lice and nits like natural pyrethrins, 1% permethrin, 0.5% malathion, and others.
Other treatment techniques involve using freezing (cryotherapy) methods or laser therapy to destroy the lice and nits. Cryotherapy uses liquid nitrogen and is performed under a special instrument called a slit lamp. Argon laser therapy uses light beams to destroy the lice and their eggs, but it needs to be done carefully to protect the eyes and may not be available everywhere.
Oral medication, like ivermectin, can also be used, but should be exercised with caution. It’s typically given in two doses about a week apart because the drug works for 16 hours at a time. However, it’s not safe for children under five years old or those weighing less than 15 kilograms or for pregnant and breastfeeding women. Ivermectin works by interfering with the nervous system of the lice, which eventually leads to the lice’s death.
Lastly, it’s necessary to take steps to stop the spread of lice to other people or parts of the body. Treating body hair infestation with anti-parasitic topical medication and/or shaving can be a solution. It’s also essential to wash clothing, pillowcases, and towels in a high-temperature water (50°C) for half an hour and then heat dried for about 10 minutes to kill lice and nits. If you or someone you know is dealing with lice, everyone in the household, including any sexual partners, should be checked for lice. Taking and maintaining these precautions is a proven strategy to minimize recontamination.
What else can Phthiriasis Palpebrarum be?
When experiencing symptoms like red eyelids, discomfort, or itchiness, there are several conditions that could be the cause. These can include:
- Seborrheic blepharitis
- Blepharoconjunctivitis
- Bacterial conjunctivitis
- Viral conjunctivitis
- Allergic conjunctivitis
- Follicular conjunctivitis
- Chalazion
- Dry eye disease
- Hordeolum
- Eyelid eczema
- Rosacea blepharitis
- Staphylococcal blepharitis
- Atopic dermatitis
- Demodicosis
- Marginal keratitis
However, these conditions should not have the phthiriasis palpebrarum organism present on the eyelashes. If this organism is detected, it could indicate a different diagnosis.
What to expect with Phthiriasis Palpebrarum
In most cases, the outlook for people with phthiriasis palpebrarum, a condition caused by lice infesting the eyelashes, is generally good. However, if the condition is neglected and the lice infestation continues for a long time, it can lead to issues like blepharitis (inflammation of the eyelids), meibomian gland dysfunction (a condition that disturbs the oil glands in your eyelids), and dry eyes. These conditions usually require specific treatments.
Possible Complications When Diagnosed with Phthiriasis Palpebrarum
- Inflammation of the eye’s eyelid, also known as blepharitis
- Long-term inflammation of the thin tissue that lines the inside of the eye, known as chronic conjunctivitis
- Dysfunction of the small oil glands located on the edge of the eyelid, referred to as Meibomian gland dysfunction
- A collection of pus in the eyelid, known as a lid abscess
- A condition causing discomfort and blurred vision as a result of inadequate tear production, commonly referred to as dry eyes
Preventing Phthiriasis Palpebrarum
If you have Phthiriasis palpebrarum, which is an infection in the eyelashes caused by lice, it’s crucial to keep good hygiene on a daily basis. This means you should wash your eyelashes with mild soaps, such as baby shampoo, every time you bathe.
This condition spreads through close contact, so family members, partners, and others you’re close to should be checked and treated if necessary. Everything that comes in contact with your eyes, like clothing, bedsheets, and towels, should be cleaned properly. Putting them in a washing machine for half an hour at a temperature of 55 degrees and using hot steam to dry them for 5 to 10 minutes can help eliminate the lice.
For clothes that cannot be washed, you should either have them dry cleaned or keep them sealed inside a plastic bag for at least two weeks. This will ensure any remaining lice are killed off, so you can safely avoid re-infection.
