Phthiriasis Palpebrarum - A Detailed Review

Introduction:

Phthiriasis palpebrarum belongs to the family Pediculidae and the genus Phthirus. It is also called eyelash lice and is rare in occurrence. It is logical for one to think that the eyelash lice would have made their way from the head. A study conducted in 2009 found that the lice reach the eyelashes through hand contact from the genital area to the eye. They hold on to the eyelid's skin, specifically at the eyelash's root.

What Are the Three Types of Lice?

Lice are tiny parasitic organisms devoid of wings and thrive on human blood. The following are the three types of lice:

• Head Lice (Pediculosis Capitis): This type manifests on the head and neck region. A sticky substance produced by the females causes the nits (eggs) to adhere to the hair shafts.

• Body Lice (Pediculosis Corporis): This type of lice lives and lays eggs on the clothing, especially on the seams, and moves to the host (humans) for feeding.

• Pubic Lice (Pediculosis Pubis): These lice are called the ‘crabs’ and are generally found in the pubic area. Like head lice, female pubic lice also produce a sticky substance that causes the nits to adhere to the hair shafts. Rarely, they can be found in areas of coarse body hair like the eyebrows, eyelashes, armpits, mustache, and beard.

What Is the Size of Pubic Lice?

An adult pubic lice or pediculosis pubis are very small and can be about 1.1 to 1.8 millimeters long. They have legs similar to a crab and cling to the hair easily. It is commonly referred to as the crab lice because of its appearance. The lifespan of the females is about 3 to 4 weeks, and they have the ability to lay three eggs daily, which hatch around 6 to 8 days later and adhere to the base of the hair.

What Is the Mode of Transmission of Phthiriasis Palpebrarum?

Lice infestation is usually associated with poor hygiene and is considered to be common in people who live in areas of poor sanitary conditions. Pthirus pubis infestation can mainly occur through sexual intercourse or in cases of interactions between an infested parent and their children. The modes of transmission are as follows:

• Mostly, pubic lice are transmitted through sexual contact in adults. Contact with someone with pubic lice infestation or their belongings are the source of nonsexual contact.

• Touching the face after touching the genital area.

• The presence of pubic lice on children's eyelashes or eyebrows can indicate sexual abuse.

What Are the Other Names of Phthiriasis Palpebrarum?

The other names are:

• Eyelash or eyebrow lice.

• Phthiriasis ciliaris.

• Ciliary phthiriasis.

What Are the Symptoms of Phthiriasis Palpebrarum?

The following are the symptoms of phthiriasis palpebrarum:

• The initial symptom is itching which is most intense at the root of the eyelashes. At times, itching can aggravate during the night since the lice are more active during this time.

• Tickling feeling.

• Redness of eyes.

• Tears.

• Eyelashes might stick together.

• Eyelashes might feel thicker.

• Brown or black spots may be noticed at the base of the eyelashes.

• Scratch marks on the skin surrounding the eyebrows and eyelashes.

How Is Phthiriasis Palpebrarum Diagnosed?

Phthiriasis palpebrarum can be diagnosed in the following ways:

• Presence of crab-like louse or their eggs on the pubic hair.

• Presence of louse or their eggs on the eyelashes, eyebrows, or in regions of coarse hair.

• White-colored eggs can be appreciated at the roots of the hair, making them appear white.

• The hair of the eyelashes and eyebrows can easily hide the nits and adult lice. This is diagnosed by a physician using a slit lamp biomicroscope under high-power magnification.

How Is Phthiriasis Palpebrarum Treated?

The presence of a few lice can be removed with fingernails or a nit comb. Other treatment methods are as follows:

• Application of ophthalmic-grade petrolatum ointment on the area of pubic lice infestation can be done. The ointment is available only on prescription. Regular petrolatum like Vaseline should not be used since it can irritate the eyes.

• Products that are not recommended for use on the eyelashes and eyebrows should not be used.

• The skin should be kept dry and cool.

• Pediculicide (medication used to treat lice) should be applied to the areas affected by the lice and not on the eyes themselves since it can cause irritation and damage. The product should be washed after 10 minutes.

• All blankets, sheets, pillowcases, undergarments, hats, or head coverings should be washed in hot water.

• Items should be dried in high heat.

• In case there is difficulty in access to washing the clothes, the clothes can be sealed in an airtight bag for two weeks to kill the parasites.

What Is the Three-Day Procedure to Treat the Lice on the Eyelids and Eyelashes?

According to a case study conducted in 2015, it has been found that phthiriasis palpebrarum (eyelash lice) can be alleviated successfully using the three-day procedure, which is as follows:

• Petroleum jelly is applied thickly to the eyelid twice daily.

• One percent permethrin shampoo is applied to the eyelid two hours after applying the petroleum jelly.

• The eyelid is washed thoroughly after ten minutes of application of the shampoo.

Before following any recommended treatment, it is always best to consult a physician and abide by their instructions. The use of commercial shampoos and ointments can irritate or damage the eyes in case of improper administration.

What Is the Differential Diagnosis of Phthiriasis Palpebrarum?

Two main differential diagnoses of phthiriasis palpebrarum are:

• Seborrheic Blepharitis: It is a condition in which the skin cells shed more excessively than normal due to a malfunctioning sebaceous gland.

• Eczema: It is a skin condition that causes itchy, inflamed, and dry patches of skin.

Eyelash lice infestation can also mimic bacterial, viral, or allergic conjunctivitis.

What Are the Complications of Phthiriasis Palpebrarum?

Some of the complications of phthiriasis palpebrarum are:

• Blepharitis (a common eye condition that can make the eyelids swollen, red, irritated, and itchy).

• Meibomian gland (a type of oil-secreting gland called sebaceous gland) dysfunction.

• Chronic conjunctivitis.

• Lid abscess.

• Dry eyes.

How Can Phthiriasis Palpebrarum Be Prevented?

Phthiriasis palpebrarum can be prevented in the following ways:

• Sensitive counseling may be required since this is a sexually transmitted disease.

• Hands should be washed thoroughly after touching the pubic region.

• Family members or sexual partners who are at risk should have their eyes evaluated or examined, and treated if required.

• Towels, bed linens, and clothes should be washed at 60 degrees Celcius for a minimum of five minutes.

• Parents or caretakers should be vigilant about the presence of pubic lice in the eyelashes or eyebrows of children as it can be an indicator of sexual abuse.

Conclusion:

Eyelash and eyebrow lice are very rare infestations of pubic lice. They can often be misdiagnosed as blepharitis or eczema. It is important to consult a physician before applying any medication or ointment to the eyes. Signs of pubic lice (phthiriasis palpebrarum) infestation in children can be a sign of sexual abuse. Applying an eye-safe product or medicated ointment to the affected area as per the physician’s recommendation can help get rid of the pubic lice.