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level: Level 1 of Chapter 15 : Infestations and Bites

Questions and Answers List

level questions: Level 1 of Chapter 15 : Infestations and Bites

QuestionAnswer
How is tx of bed bugs?• Bites will typically resolve within 1-2 weeks • For symptomatic relief, treat with potent topical steroids and antihistamines • Ultimate treatment requires detection and eradication of the household infestation • Bed linens need to be laundered and furniture vacuumed
NANA
What is pediculosis (lice)?• Three different varieties of lice may infest humans Head lice – Pediculus humanus var. capitis • Body lise – Pediculus humanus var. corporis • Pubic or crab louse – Phthirus pubis • Head lice are spread by close physical contact (brushes, helmets, bedding) • Commonly affects school-age children • Affects all ethnic and socioeconomic groups, but is less common in African-Americans
What are clinical features of pediculosis?• Frequently associated scalp pruritus • May also have posterior cervical lymph nodes • Dermatitis may be present on the posterior neck • Nits are noted more commonly than lice on exam (live lice scurry away from light) • The most common sites to find nits are on the retroauricular and occipital scalp • Nits within 1 cm of the scalp are typically viable. The distance may be greater in warm environments • Nits must be distinguished from hair casts. Hair casts encircle the hair shaft and move freely in contrast to the nit which is cemented to the hair
How is pathogenesis of pediculosis?• Female adult lice live 30 days and lay 5-10 eggs (nits) per day at the base of the hair where it meets the scalp • Eggs hatch in 8-12 days • Live eggs remain close to the scalp to maintain warmth and moisture but as the hair grows, the nits move off the scalp with the hair • Because hair grows at a rate of ~ 1 cm per month, the duration of infestation can be estimated by the distance of the nit from the scalp • The adult head lice is 2-3 mm in length and has six legs • The presence of live adult lice, immature nymphs, and/or viable eggs indicate active infestation • Lice typically survive 1-2 days away from the scalp. Eggs may survive up to 10 days away from the scalp
How is tx of lice?• Individual patient factors should be assessed prior to choosing a topical therapy (age, allergy history, prior treatment, etc.) • It is prudent to re-treat with topical therapies 7-9 days after initial therapy to kill the newly hatched lice • First-line over-the-counter and prescription topical therapies are listed on the following slide. Use OTC permethrin 1% or pyrethrins when resistance is not suspected • Malathion 0.5% when resistance to permethrin or pyrethrins is documented or when treatment with these products fails • Adjunctive nit combing can be performed • Occlusive methods have also been used to suffocate head lice using substances such as petroleum jelly, but study results have been variable
How is pt education regarding lice?• All poeple living in the home should be examined to avoid re-infestation • Those with live lice or nits within 1 cm of the scalp should be treated • It is recommended to treat family members who share a bed with the person with infestation, even if no lice are found • If it is not possible to examine household members, treat without an exam if the treatment is not contraindicated
How is management of clothes in lice?• Clothing and bedding should be washed and dried on the hot cycle of the dryer • Brushes, combs and other hair care items can be placed in hot (> 60°C) water for 10 minutes • Non-washable items may be placed in the dryer or stored in a sealed plastic bag for 3 days • Children should not be restricted from attending school because of lice
What are bed bugs?• Cimex lectularius (most common type) affect people from all racial and socioeconomic groups • May be spread during travel on clothing, bedding, mattresses, and laundry, etc • Stay hidden during the day and feed at night • Bites may be multiple in a linear array; referred to as “breakfast, lunch and dinner”
How is clinical presentation of bed bugs?• Usually present as pruritic, erythematous and edematous papules • Onset and duration of lesions vary depending on the patient's degree of sensitization • Some individuals have little or no reaction to bedbug bites • Common for only one or a few family members (even among those sleeping in the same bed) to report lesions • Red-brown in color with a segmented abdomen and vestigial wings
How is tx of bed bugs?• Bites will typically resolve within 1-2 weeks • For symptomatic relief, treat with potent topical steroids and antihistamines • Ultimate treatment requires detection and eradication of the household infestation • Bed linens need to be laundered and furniture vacuumed