treatment plan

Differentiating the Red Eye (Part II): When It's Not "Pink Eye"

BY BRUCE E. ONOFREY, RPH, OD
November 1999

One of our receptionists asked if we could take a look at her teenage daughter's eye, which she thought had been infected with the "pink eye" that had been going around the school.

The patient was a 17-year-old with intense itching of her upper left eyelid. Her symptoms had begun approximately 10 days previously and had progressively gotten worse. She reported that foreign body sensation and burning were worse in the morning and improved slightly during the day. She stated that her boyfriend had complained of similar symptoms approximately 1 week prior to the start of her own. See Table 1 for the patient's exam results.

Although viral infections and other less virulent adenoviral infections are common, sexually transmitted diseases should be considered in sexually active individuals. A patient's medication history is another important consideration. Acne medications can cause profound ocular irritation.

Nit cases on the lashes of her left eyelid led us to the inevitable diagnosis of ocular pediculosis. The reddish fecal material present on the lid margin was also a telltale sign. Lice infestations associated with the eyelashes are almost always associated with the pubic or crab louse, Pthirus pubis, which prefers the spacing of the eyelashes since it's similar to the spacing of the pubic hair. Because the symptoms of pubic louse infestation include itching and lid inflammation, it's not uncommon for an inexperienced clinician to misdiagnose the condition.

Treatment Options

You can attempt to remove small lice infestations with forceps, but because they cling so tenaciously, this task may be difficult. Some practitioners use a cryoprobe or argon laser to destroy the parasites, but the safest method of treatment consists of thick applications of white petrolatum or 1-% yellow mercuric oxide ointment (Sty ointment, Del Pharm) to the affected area twice daily. This treatment smothers the adult lice, but must be continued for up to 2 weeks to kill hatchlings. Physostigmine can also be used to poison the adult louse and must also be continued for up to 2 weeks to kill hatchlings.

Due to side effects, however, most clinicians reserve these products only for patients who don't respond to more conservative therapy.

A Not-So-Happy Ending

Although these patients require significant counseling and their partners must be treated to prevent immediate reinfection, they are often reluctant to give the names of their partners and commonly do not return for follow-up visits, such as in this case.

The patient was given a prescription for Lindane 1% shampoo and advised to use Lacri-Lube NP Ophthalmic Ointment (Allergan) three times daily on the lids for 2 weeks. She was also told to clean all of her bedding in hot water. Although this is a difficult subject to broach, clinicians must attempt to counsel their patients in order to prevent the spread of this parasite.

Dr. Onofrey, editor and author of various ophthalmic texts, practices in Albuquerque, New Mexico.