"Pediculosis and Scabies: A Treatment Update" (My Synopsis)

Pediculosis and Scabies: A Treatment Update
KAREN GUNNING, PharmD, University of Utah College of Pharmacy, Salt Lake City, Utah KARLY PIPPITT, MD, University of Utah School of Medicine, Salt Lake City, Utah BERNADETTE KIRALY, MD, University of Utah School of Medicine, Salt Lake City, Utah MORGAN SAYLER, PharmD, University of Iowa College of Pharmacy, Iowa City, Iowa
Am Fam Physician. 2012 Sep 15;86(6):535-541.

     Pediculosis is an infestation of lice on the head, body, or pubic region. The typical presentation is pruritus after 2-6 weeks of infestation. Since it is a delayed hypersensitivity reaction, subsequent infections will cause itching in 1-2 days. Constant scratching will lead to excoriations, lichenification, hyperpigmentation, and cellulitis. Diagnosis is made when a live louse is found. Finding a nit (a louse egg) is not diagnostic.  A good place to check for head lice is behind the ears and on the back of the neck. When a diagnosis is made, all members of the household should be examined and treated. Washing clothing, bedsheets, and towels (fomites) in hot water (122° F) will eradicate the parasites. Pubic lice can will be found in pubic hair and the seams of clothing. Patients who present with pubic lice should be checked for other STI's as well. 
     First line treatment is with permethrin. It is left in  the patients' damp hair for 10 minutes once a week. Two treatments should be effective. Resistant communities (such as England) can be treated with malathion. Oral ivermectin is a second line medication when there is resistance to either topical treatment. Nonpharmacologic treatments include wet combing with a lice comb and a leave-in conditioner. Another option to consider is to apply Cetaphil Gentle Skin Cleanser to the scalp, comb out after two minutes, dry with a hair dryer, and shampoo the hair after 8 hours. 
     Scabies presents with a generalized itchy rash, which is worse at night.  It may present as excoriations, eczemations, pyoderma, papules, nodules, or vesicles. The face and neck are spared (except in infants).  A burrow type lesion (short, gray, wavy lines) may be found on the hands, feet and in the finger webs.  Diagnosis can be made by finding a mite, egg or fecal matter on a skin scraping of the lesion. Treatment consists of permethrin cream on the entire body (neck down) for 8-14 hours. A second treatment can be done a week later. The pruritus may continue for up to two more weeks.  Oral ivermectin is second line therapy (due to cost).  Cloth washing should be at 140°F and with a hot clothes dryer.
     Norwegian scabies (or crusted scabies) presents as a generalized scaling, nail abnormalities, and thick, crusted lesions on the feet and hands. Pruritis is not present or minimal. An outbreak may have thousands of mites on the body, whereas in traditional scabies, there may only be a dozen. It is tougher to treat as well. Treatment includes daily permethrin cream and frequent oral ivermectin.