Ectoparasites – scabies and lice – are often seen in the correctional environment, especially in the jail population. Correctional nurses must know the usual treatments that may be ordered for their patients with an infestation. They also must be knowledgeable about the patent education that is required for their patients to help prevent spread the infection, and to ensure that the patient understands their treatment plan.

PHARMACOLOGICAL TREATMENT

The mainstay of scabies and lice treatment has been the application of topical scabicidal/pediculicide agents, with repeat application in 7 days. The treatment of choice is permethrin 5% lotion. A 2007 Cochrane Review found that topical permethrin appeared to be the most effective treatment for scabies. Alternative drug therapy includes lindane and ivermectin. Lindane is the application of choice for lice. Ivermectin is typically dosed at 200 mcg/kg, and a second course of treatment is often recommended 7-10 days later because of some developing larvae that may survive the initial treatment. Pruritus can be treated with an oral antihistamine, such as hydroxyzine hydrochloride (Atarax), diphenhydramine hydrochloride (Benadryl), or cyproheptadine hydrochloride (Periactin). More severe symptoms may require a short course of topical or oral steroids. Secondary infections may require antibiotics, which should be prescribed based on culture and sensitivity data.

Permethrin (Acticin, Elimite) 

A neurotoxin that causes paralysis and death in ectoparasites, permethrin 5% cream is the drug of choice for scabies treatment, especially in infants over age 2 months and small children. It may reduce chances of secondary bacterial infection.   The lotion should be applied over the entire body to clean, dry skin. It should be left on for 10-14 hours and then rinsed off. Reapplication 1 week later is advised; however, no controlled studies have demonstrated that two applications are more effective than one. Permethrin is a pregnancy category B.

This is available in 1% lotion or cream. Lindane stimulates the nervous system of parasites, causing seizures and death. It was previously the standard treatment for scabies but is now considered a second-line drug, to be used if other agents fail or are not tolerated. Some scabies have been found to be resistant to Lindane. Lindane is not safe in children or neonates, because of increased transcutaneous absorption leading to possible neurotoxicity. It is a pregnancy category C and should not be used in pregnancy. The systemic absorption rate of lindane is 10 times greater than that of permethrin, and its serum levels are more than 40 times higher. Overall, Permethrin is a safer choice.

Ivermectin binds selectively with glutamate-gated chloride ion channels in invertebrate nerve and muscle cells, causing cell death. It is available in 3- and 6-mg tablets. The drug is currently approved for the treatment of human onchocerciasis and strongyloidiasis. Although it is not approved by the FDA for the treatment of scabies and lice, it is widely administered for this purpose, with the literature supporting its use. Ivermectin is active against a number of endoparasites and ectoparasites of humans and animals. Ivermectin is an ideal agent in cases where topical therapy is difficult or impractical, such as in widespread institutional infestations and bedridden patients. Patients with crusted scabies may require 3 or more doses, given at 1- to 2-week intervals. Ivermectin is contraindicated in patients with allergic sensitization or nervous system disorders, and in women who are pregnant or breastfeeding.

Topical Antibiotics 

These agents may be used to treat secondarily infected lesions, although oral medication may be more efficacious.

Mupirocin (Bactroban, Centany) 

This agent is used to treat infection with Staphylococcus species, beta-hemolytic streptococci, or Streptococcus pyogenes. It inhibits protein and ribonucleic acid (RNA) synthesis by inactivating transfer-RNA synthetase.

These agents may be applied to help control intense pruritus caused by scabies.

This is an adrenocorticosteroid derivative that is suitable for application to skin or external mucous membranes. It has mineralocorticoid and glucocorticoid effects that result in anti-inflammatory activity. Hydrocortisone is considered the lowest-potency topical steroid.

Complications 

Frequent use of scabicidals/pediculicides may cause persistent itching. Body lice can be vectors for diseases such as epidemic (louse-borne) typhus, trench fever, and louse-borne relapsing/recurrent fever. Violation of the integrity of the skin from a bite can lead to bacterial infection with organisms such as methicillin-resistant Staphylococcus aureus (MRSA). More commonly, infestation with ectoparasites produces social embarrassment and isolation rather than medical disease. There is no evidence indicating that any species of ectoparasite have the ability to transmit HIV. However, lice may carry S aureus and group A Streptococcus pyogenes on their surface and transmit these coagulase-positive pathogens to humans. The body louse, P humanus corporis, is a known vector of 3 major bacterial diseases, all of which have caused epidemics: louse-borne typhus, trench fever, and louse-borne relapsing fever.

Follow-Up

Patients with scabies may need to be reexamined at 2 weeks and again at 1 month after treatment. If a patient has lesions at the 1-month check-up, reinfection or persistent infection should be suspected, and treatment should be reinitiated. The patient’s roommates or any close contacts should also be examined to check for a source of reinfection. Patients with crusted scabies, especially, should be followed after treatment and may require repeated courses of treatment.

TREATMENT FAILURE

While treatment failures are uncommon, they may occur for the following reasons:

• Improper application
• Inadequate application
• Reinfestation – Recurrence of the eruption usually means reinfection has occurred, underscoring the importance of treating all members of the household
• Resistance –  Resistance to lindane has been widely reported;  less frequently, cases of resistance to permethrin have been noted;  resistance to ivermectin is still rare but has been reported in patients who received multiple doses of the drug over several years.
• Neonates and pregnant women should be treated for scabies only if the benefit exceeds the risk and if the diagnosis is confirmed by a positive skin scraping or biopsy result.
• Crusted scabies may require several treatments with scabicides and sometimes several different medications used sequentially.
• Scabetic nodules may require intranodular steroid injection.

PREVENTION 

All roommates and close personal contacts at the facility should be treated for scabies, even if they have no symptoms or signs of infestation. Detailed directions regarding treatment and environmental control measures should be provided verbally and in writing to the individual and the officers in the housing unit from which the infected individual came. New linens and clothing should be given to the patient to be changed after treatment. Clothing, bed linens, and towels used within the last week should be laundered in hot water (60°C or higher) and machine dried the day after treatment is initiated. Any item that cannot be washed should be sealed in plastic bags for one week.

PATIENT EDUCATION

The social stigma associated with ectoparasite infestation must be addressed. Poor hygiene is not a risk factor in acquiring pediculosis capitis, although it is for body lice. Management of head lice must include examination of all individuals exposed (all roommates and other close contacts) and treatment of all those who are infested. Individuals who have no evidence of infestation should not be treated.

Noncompliance is a common cause of treatment failure in ectoparasite infestations. Therefore, it is important that patients are given detailed instructions regarding the application and timing of lotion medications if used in their treatment. Oral medication side effects and dosing should also be shared with the patient. Fomites may harbor live lice and therefore should be treated to prevent re-infestation and infestation of other individuals.

All sexual partners from within the previous month of a person infested with pubic lice should be treated. Patients should be encouraged to share their condition with any sexual partners, inside the facility or in the community. Sexual contact should be avoided until both parties have been successfully treated.

Infested clothing, linens, and towels should be washed in hot water and dried with a hot dryer. The infested individual should be counseled on proper hygiene, changing clothing per the facility change-out policy, and the proper laundering of clothing.

This is our final post in the three-part series Ectoparasites. In our previous posts, we discussed the scabies and lice ectoparasite.

**This Ectoparasite series is based upon The Correctional Nurse Educator class, Ectoparasites in the Correctional Environment.

Please share your challenges with the care of patients with an ectoparasite infestation in the comments section below.