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Pediculosis humanus capitus, the head louse, is a blood-sucking, obligate parasite that can lead to significant infestation and both direct and indirect medical costs. Treatment can become complicated with outbreaks and increasing resistance.
A 52-year-old, wheelchair-bound, paraplegic man with a history of pemphigus foliaceus well controlled by azathioprine presented for scalp pruritus. The patient had extensive dreadlocks, which he had grown for decades, since the accident that had paralyzed him (Figure, A). On examination, he also had adherent white nits along his dreadlocks and multiple visibly mobile insects close to his scalp. He was diagnosed with a florid infestation of P humanus capitus (Figure, B).
A, Hair in extensive dreadlocks extending to the floor was infested with head lice. B, One of the many lice removed from the patient’s head.
Several treatment options were presented to our patient but rejected. He attempted home remedies of topical lotions, which were unsuccessful. Our patient adamantly refused to consider cutting his hair and was not amenable to washing or combing of his dreadlocks. The patient further declined oral therapies, concerned about drug-drug interactions and too many medications. Alternative treatment options were considered, and the patient was treated at a local Lice Lifters center (Philadelphia, Pennsylvania) using Louse Buster nonpesticidal therapy (http://www.licelifters.com) with resolution of his infestation and retention of his dreadlocks.
Pediculosis humanus capitus is a 6-legged, obligate parasite that can cause persistent pruritus and excoriations secondary to inflammation from the saliva and fecal matter; persistent itching can occur for weeks even after treatment. In addition, infrequent bacterial superinfection can occur, and these lice can rarely serve as a vector for Yersinia pestis or Bartonella quintana.1,2 The female louse lives for 3 to 4 weeks and can lay up to 10 eggs per day; these eggs hatch in 7 to 12 days and then complete their 3 nymph stages before maturing into an adult form. This cycle repeats every 3 weeks.3 Although adult lice typically survive for up to 30 days with blood meals, they cannot live more than 48 hours away from a feeding source.3 Transmission is most common with direct head-to-head contact, although indirect transmission through fomites can occur and is preventable with laundering at high temperatures that kills both the lice and nits.
Ideal therapy for head lice infestation includes ovicidal and pediculocidal topical medications that impact the louse’s nervous system. First-line therapy includes permethrin and pyrethrins, although resistance is becoming increasingly common.4 Older second-line topical therapies also include lindane and malathion, which have safety concerns with flammability and toxic effects, and new topical treatments include benzyl alcohol, spinosad, and ivermectin.5,6 All of these topical treatments require thorough washing of the hair after application and can have adverse effects such as irritant and contact dermatitis if left in place; rare toxic effects also has been reported with application. Oral ivermectin and trimethoprim-sulfamethoxazole are parenteral agents that have been reported to be efficacious in widespread or resistant infestations. Nonpesticidal therapies also include fine-tooth combing; topical application of petrolatum jelly, mayonnaise, or olive oil; meticulous manual removal; or shaving of the head.3
We present a challenging clinical case in an immunosuppressed host complicated by our patient’s extensive infestation involving his dreadlocks. Traditional topical therapies were not possible without washing because of concerns for topical allergic or irritant dermatitis, and physical methods such as combing out the nits and cutting the hair were refused by the patient. Oral medications were considered but also refused. The Lice Lifters center provided a program and combined intensive topical, nontoxic treatments at a local center and at home and manual removal of nits. These techniques should be considered when traditional therapies are not possible.
Corresponding Author: Misha Rosenbach, MD, Department of Dermatology, University of Pennsylvania, 3600 Spruce St, Philadelphia, PA 19104 (firstname.lastname@example.org).
Published Online: June 26, 2013. doi:10.1001/jamadermatol.2013.4419.
Conflict of Interest Disclosures: None reported.
Wanat KA, Rosenbach M. A Dreadful Infestation. JAMA Dermatol. 2013;149(8):993–995. doi:10.1001/jamadermatol.2013.4419
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