Infestations Flashcards
What is pediculosis capitis?
- Head lice
- Causes intense pruritis of scalp
Where is pediculosis capitis common?
- Highly contagious often in schools and day care centers
- Anywhere that people live in close quarters: nursing homes, dorms, prisons
head lice
Characteristics of louse in pediculosis capitis
- 1-3 mm long, flattened brownish gray elongated bodies, 3 pairs of legs and claws
- Small, wingless ectoparasites
- Lifespan 14-18 days
- Nits .5-1 mm in diameter and opalescent, grey-white specks firmly attached to individual hair shafts
- Microscopy reveals oblong structure attached to hair at acute angle with lobular breathing apparatus at its superior end
Where is pediculosis capitis/pubis nit found? Humanus?
- Capitus/pubis: hair shaft
- Humanus: seams of clothing/bedding
Epidemiology of pediculosis capitis
- MC in females
- White school aged children/mothers
- Warmer months
How can you differentiate between seborrheic dermatitis and pediculosis capitis?
- Seborrheic dermatitis: greasy, yellow, irregular scales that are easily removable
- Pediculosis capitis: adhere to hair shaft
How do you differentiate between pediculosis capitis and tinea capitis?
- Tinea capitis has pruritis and lymphadenopathy but is associated with alopecia and no nits found on examination
How do you differentiate between pediculosis capitis and psocid lice?
- Psocid lice live off plant detritus and may be found on child who plays in wooded areas but are morphologically distinct from pediculosis humanis capitis
Transmission of pediculosis capitis
- Direct head-to-head contact
- Fomites (clothes, brushes, linens, combs, hats)
- Lice live approx 30 days on host and <1 day off host
- Eggs hatch within 7-10 days
What should you look for in the scalp hair in pediculosis capitis?
- Lice and nits in scalp hair
- Maculae ceruleae or purpuric stains on skin of occipital scalp and nape of neck
- Occipital lymph nodes may swell as result of secondary infection
Diagnostic pearls for pediculosis capitis
- Pyodermas (infection with bacteria causing pus under the skin) in the scalp along with occipital and cervical lymphadenopathy suggestive
- Nits oval, tenacious hair concretions
- Nits not easily removed from hair (unlike seb derm)
- Nits fluoresce and are readily detected with a wood’s lamp
Best tests for pediculosis capitis
- Demonstration of lice or nits on hair visually or under microscope
- Wood’s lamp with fluorescent nits
Management pearls for pediculosis capitis
- Increasing resistance of lice to permethrin. If no response with permethrin, use alternative
- Manual nit removal with fine comb may be used as adjuvant to topical therapy
Precautions for pediculosis capitis
- Standard and contact
- Isolate patient
- Wear gowns and gloves
- Limit patient transport
- Avoid sharing patient-care equipment
Treatment of pediculosis capitis
- Prescriptions reserved for patients with proven infestations that do not respond to OTC
- Manual nit removal with fine comb adjuvant to topical therapy
- Most herbal and home remedies unproven in effectiveness and safety
- Do not treat a child unless live lice or eggs (not empty nit cases) present
OTC for pediculosis capitis
- Permethrin 1% (Nix): apply to dry hair, rinse after 10 minutes
- Repeat in 1-2 weeks
- Pyrethrins with piperonyl butoxide (RID, pronto): apply to dry hair, rinse after 10 minutes
- Repeat in 1-2 weeks
Prescriptions for pediculosis capitis
- Spinosad- adults and children older than 4 years
- Malathion .5% lotion
- Permethrin 5%: not for infants younger than 2 months
- Ivermectin formulated lotion: adults and children 6 months and older, not used in babies younger than 6 months or pregnant women
- Oral ivermectin: not for children younger than 5 or weighing less than 15 kg
How is spinosad applied?
- In adults older than 4 years
- Applied for 10 minutes if live lice seen at 1 week second treatment
- Combing not necessary
What is the first line lice treatment by the american academy of pediatrics?
Spinosad
How is malathion applied?
- Apply to dry hour and rinse after 8-12 hours
- Repeat after 1-2 weeks
How is permethrin 5% applied?
- Off label
- Apply to dry hair, rinse after 8-12 hours
- Repeat in 1-2 weeks
- Not in infants aged younger than 2 months
How is ivermectin formulated lotion applied?
- Treatment applied for 10 minutes
- Adults and children 6 months and older, not used in babies younger than 6 months or in pregnant women
How is oral ivermectin (off-label) used?
- 200 micrograms/kg in one oral dose
- Repeat in 7-10 days
- Not indicated in children aged younger than 5 years or weighing less than 15 kg
How is pediculosis capitis with eyelid involvement treated?
- Application of petrolatum twice daily to eyelid margin for at least 8 days
What is pediculosis corporis?
- body lice
- Infestation with pediculosis humanis corporis
- 2-4 mm, wingless, blood-sucking arthropod whose preferred hosts are human beings
- Rarely found on skin, mainly clothing
Signs and symptoms of pediculosis corporis
- Extremely pruritic, especially at night (lice move from clothing to body to feed)
- Bites leave macules and papules concentrated in intertriginous regions
Epidemiology of pediculosis corporis
- Found in all countries and climates
- May infest any age group
- No racial or sex predilection
- Associated with poor hygiene, poverty, and homelessness
Clinical manifestations of pediculosis corporis
- Multiple erythematous papules that correspond to insect bites
- Found anywhere on body but most concentrated in areas covered by clothing: groin, axillae, trunk, buttocks
- Maculae cerulea, blue-gray macules pathognomonic for lice infestation may be present
- Excoriations and/or impetiginization
- Exam of clothing may reveal nits, feces, blood stains, or insects themselves
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What is “vagabond disease?”
- Body louse infestation
- Individuals that are infested for years may develop vagabond skin - thickened and darkened skin after a long period of bites and scratching or rubbing
Best tests for pediculosis corporis
- Close examination of clothing for lice, nits, and feces (most concentrated at clothing seams)
- Finding of a live louse or viable nit confirms diagnosis
- Wood’s lamp fluoresce yellow-green
- Can shake patient’s clothing out over white paper and examine the debris that falls off - pieces of tape can be used to pick up insects for exam
Management pearls for pediculosis corporis
- Examine patient for pubic and head lice
- If clinical suspicion warrants, test for one of arthropod borne diseases transmitted by p. humanus corporis –» typhus (rickettsia prowazekii), relapsing fever (borrelia recurrentis), trench fever (bartonella quintana)
- Mainstay of treatment = eradicating infestation
Precautions for pediculosis corporis
- Standard and contact
- Isolate patient
- Wear gloves and gown
- Limit patient transport
- Avoid sharing patient-care equipment
Patient education for pediculosis corporis
Proper hygiene
Treatment of pediculosis corporis
Treat clothing and fomites
* Wash all clothing and linens with hot water and dry on high heat
* Discard or avoid using heavily infested items for 2 weeks (seal in plastic bags)
* Iron seams of furniture with hot iron
* For heavy infestations 5% permethrin cream or lotion head-to-toe for 8-14 hours
What is pediculosis pubis?
- Pubic lice or crabs
- Highly contagious
- Sexually transmitted parasitic infection with louse, phthirus pubis
How is pediculosis pubis spread
- Person to perosn by close physical contact
- Occassionally spread via fomites such as clothing or linens
- Household pets do not play role in transmission
Where/who most commonly has pubic lice
- Sexually active individuals
- Terminal hair, typically pubic and perianal regions
- Infestations may also be in eyelashes, eyebrows, and other facial hair, as well as chest and axillary hair
- Scalp infestations in tightly curled hair
Progression of pediculosis pubis
- Incubation > 1 week from contact
- Eggs (nits) cemented to hair shafts with chiin and difficult to remove
- Lice hatch in 6-10 days
- Lifespan = 1 month
- Not able to survive without feeding within 24 hours
Chitin = fibrous substance consisting of polysaccharides and forming constituent in exoskeleton of arthropods
Clinical manifestations of pediculosis pubis
- Extreme pruritis secondary to saliva/anticoagulant injected during feeding
- Lice visible to naked eye
- Erythematous macules or papules present at feeding sites
- Wheals can be appreciated as acute reaction
- Small pinpoint bleeding on intimate clothing
- +/- inguinal lymph node swelling
- +/- maculae cerulae, or blue-gray macules seen at feeding sites on patients with long standing infestation
Appearance of lice/nits in pediculosis pubis
- Lice visible to naked eye and with dermatoscope 1-3 mm in diameter, nits smaller but may be visible and tightly adhered
- Adult louse with legs grasping hair shaft and insertion of mouth to skin
- Nits - brown and full in shape, indicating presence of a nymph, or more translucent and flat in shape when empty
- Nits may be mistaken for crusts or hair casts when attached near the ostia of hair follicles
Clinical diagnosis of pediculosis pubis
- Severe pruritis = main symptom
- Physical exam and additional tools such as dermoscopy, tape for specimen collection, or Wood’s lamp for fluorescence of nits may prove useful
- Evaluate all hair bearing areas including facial hair, axillary hair, and chest hair
- Finding louse is diagnostic
Management pearls for pediculosis pubis
- Sexual partners within the prior month should be notified and treated
- Avoid sexual contact until they and their partners have been treated and reevaluated to rule out persistent disease
- Condoms do not prevent transmission of infestation
- 30% have another STI so ROS and lab screening encouraged
- Thorough history to recognize abuse or neglect if child