Delousing the Eyelids
By William L. Miller, OD, PHD, FAAO
Although an uncommon cause of ocular infection, the presence of eyelid lice represents a public health issue for your practice and an important cause of blepharitis. Pediculosis and Phthiriasis, like Demodicosis, are ectoparasitic infestations of the eyelids.
Phthirus pubis, the more common of the two lice to infiltrate the periocular region, is a pubic crab and is more frequently found in the genital and inguinal area as well as in axillary chest hair. Phthirus is transmitted via sexual contact and is likely spread manually to the periocular lashes and eyebrow. Infestation can also be transmitted by sharing hats and combs as well as items such as towels and bed linen.
Signs and Symptoms
Patients may complain of bilateral itchy eyes, eye redness, and ocular or periocular irritation. For these reasons, both conditions can be misdiagnosed as seborrheic or rosacea blepharitis, allergic dermatitis, eczema, or conjunctivitis. Patients may be susceptible to secondary bacterial infections from the excoriated areas of lice infestation and may have a concurrent lymphadenapathy.
To pinpoint the diagnosis, take a detailed history including a review of systems and perform a careful biomicroscopic examination. The lice are most easily detected on the lashes by searching for blue bite marks (maculae ceruleae), translucent brownish oval nits (egg sacs), or remnant reddish-brown feces near the base of the lashes. The Phthirus pubis and pediculosis lice are between 1mm to 2mm in length and can be difficult to detect due to their transparent bodies, although they may be seen quickly moving as the biomicroscope beam traverses their resting place adjacent to individual lashes.
Treatments that are often used for the body and scalp, such as permethrin 1% or pyrethrinpiperonyl butoxide 0.33%, are not recommended due to their toxicity to the ocular surface. Treatment options for eyelid lash involvement have included 20% fluorescein, 1% yellow mercuric oxide, 2.5% permethrin cream, and physostigmine.
Mild infestations can be treated through direct removal. Using a biomicroscope or magnification loupe, each louse is individually removed using forceps or adhesive tape applied to the lashes. The lashes can also be removed or trimmed to eliminate the attached lice. However, in all but the complete removal of the lashes the lice may remain, thus an application of an occlusive ointment such as Refresh Lacri-Lube (Allergan), DuoLube (Bausch + Lomb), or Vaseline for 10 days to 14 days is advisable. Remember that occlusive therapy is not ovicidal; additional visits may be required to remove newly hatched lice. Also advise patients to wash all linens and towels in the highest heat setting.
Moderate to severe manifestations of palpebral lice can be treated with prescription topical and/or oral medication. Complete eradication from the eyelid lashes may take one to two weeks depending on the severity of the presenting case. Ivermectin (250 mcg/Kg) taken orally has also been suggested, although it is not clinically indicated for this purpose (Burkhart and Burkhart, 2000; de Pinho Paes Barreto et al, 2012). Pilocarpine gel 4% applied to the eyelid margins and lashes as well as malathion 0.5% lotion have been used topically to rid the eyelashes of lice (Pinckney et al, 2008; Vandeweghe and Zeyen, 2006). Malathion lotion or 1% shampoo have not been proven safe nor are they approved for periocular use. Pinckney et al (2008) strongly advocate the use of Pilopine HS (Alcon) along with a bland ointment for complete eradication of the lice. CLS
For references, please visit www.clspectrum.com/references.asp and click on document #202.
|Dr. Miller is an associate professor and chair of the Clinical Sciences Department at the University of Houston College of Optometry. He is a member of the American Academy of Optometry and the AOA where he serves on its Journal Review Board. He is a consultant or advisor to Alcon and Vistakon and has received research funding from Alcon and CooperVision and lecture or authorship honoraria from Alcon and B+L. You can reach him at firstname.lastname@example.org.|