Head lice; formaldehyde storage; chewing gum in the OR; building design

AORN Journal, March, 2000 by Ramona Conner

Question: We have many surgical patients who come to our facility with untreated head lice (Pediculus humanus capitis), and we cancel the elective surgery until the patient is treated. Is this correct procedure? What controls should be implemented when the surgery is on emergency and cannot be delayed for treatment of the lice? How do we protect employees and patients from the transmission of lice?

Answer: Treating the patient before elective surgery may be the preferred practice. Literature shows that nosocomial transmission of head lice is rare but possible. Head lice are not vectors of specific serious disease, but if they are not treated, complications may arise, including secondary bacterial infections such as impetigo, pyoderma, and lymphadenopathy.(1)

Head lice infestations have been part of human history since the beginning of recorded time. Nit combs have been found in the Judean desert dating back to 68 AD. With the development of dichlorodiphenyltrichloroethane (ie, DDT), head lice was almost eradicated during World War II. Them was, however, a resurgence of head lice in the 1960s, and the incidence continues to rise.

No area in the United States is immune to head lice. An estimated six to 12 million people are affected each year. Children between the ages of five and 12, girls more often than boys, are affected most often. More infestations occur among children with brown or red hair than among those with black or blond hair. Some children are prone to repeated infestations, and others are unaffected. Large families are infested more often than small ones, probably due to proximity rather than socioeconomic status.(2)

Head lice are attracted to people with fine hair rather than coarse hair. Except for the African-American population, lice infestation occurs in all races and socioeconomic levels. A low incidence among African-American families is attributed to the shape of the hair shaft.(3) Individuals with good personal hygiene practices are more vulnerable than people with long, dirty hair and scalps. Head lice actually prefer a clean environment.(4)

The head louse is an external parasite of the human host. It is 2 mm to 4 mm long with six clawlike legs and a flat, grayish-brown, wingless body. It lives on hair near the scalp where it finds food and warmth, feeding by sucking the host's blood. Itching is caused by injection of louse saliva into the scalp.

Transmission is through person-to-person contact by direct, even brief, head-to-head contact. Lice cannot jump or fly, but they can crawl up to 12 inches. During the average 30-day life span of the louse, the female attaches 60 to 150 eggs, commonly called nits, to hair shafts near the scalp with a sticky, gluey substance. The nits hatch into a nymph, or immature louse, in seven to 10 days. The louse reaches maturity in approximately two weeks.

The adult louse usually feeds every four to six hours, but it is capable of surviving for two days without a host. Nits will survive without a human host for up to 10 clays but will not hatch in temperatures below 71.6 [degrees] F (22 [degrees] C). Temperatures greater than 125 [degrees] F (52 [degrees] C) for a period of five minutes is lethal to nits and the adult louse.(6)

Many experts believe that transmission can occur indirectly by contact with clothing, bedding, or personal grooming items such as combs, hats, and scarves. In general, the risk of nosocomial head lice transmission is very low unless there is an opportunity for direct contact. Some authorities consider any head lice that fall off the scalp on pillows, clothing, or bed linens to be generally sick and unlikely to be able to establish themselves on another head.(7)

When delay of surgery is not a reasonable option, careful use of contact precautions and implementation of the AORN "Recommended practices for environmental cleaning in the surgical practice setting" should effectively minimize the risk of transmission.(8) The life cycle of the louse is dependent on availability of a human blood meal and moderate temperature. Louse viability is possible between 59 [degrees] F (15 [degrees] C) and 100.4 [degrees] F (38 [degrees] C), which are common temperatures found in most OR suites. Combs and brushes, if used, should be cleaned in hot water. All bed linens, pillows, towels, clothing, and nondisposable headwear should be placed in a sealed plastic laundry bag and laundered by the facility-approved commercial laundry. If a commercial laundry is not available, these items should be machine washed in hot water and dried in a hot dryer. Disposable supplies should be discarded in the normal appropriate containers and sealed. The OR should be cleaned according to routine procedures, using the hospital-approved disinfectant. Pesticide sprays are not necessary.(9)

Perioperative nurses and other health care workers exposed to patients with head lice do not require treatment unless they show evidence of infestation, t" Treatment for the patient or the unfortunate infested employee includes use of one of three currently available pesticidal agents: 1% lindane shampoo, 0.3% pyrethrin shampoo, or 1% permethrin cream rinse. The medication of choice is 1% permethrin cream rinse, which has been found to have the greatest efficacy and widest margin of safety. It is photostable and 99% ovicidal and does not require repeated applications.