Lice and Scabies Flashcards
What is the impact of lice?
1) causes concern and stress among infected individuals - lowers QOL
2) social stigma surrounding infestation
3) significant amount of absenteeism from work and school
How many lice are typical for a lice infestation and how long will they live without treatment?
<20 mature head lice
Will live 3 to 4 weeks if left untreated, feeding every 3-4 hours
How is head lice transmitted?
Head to head contact
How long can lice live?
21-27 days, the females can lay ~4 eggs per day
Away from the host, the head lice will die within 1-2 days
How does itching develop in individuals infested with lice?
Itching occurs if the host becomes sensitized to antigenic components in the saliva injected as the louse feeds
* some people remain asymptomatic
How do you diagnose an active lice infestation?
Find one live louse
Nits do not mean that there is an active infestation, especially if they are further than 6mm away from the scalp
How do you perform an inspection of air to find nits?
Comb wet hair systemically with small parts at a time, saturated with white conditioner to make it harder for lice to move quickly out of view
NEED A LICE COMB with spiral groove to dislodge nits
Contents of the comb and materials need to be examined and removed after EACH brush through
When should you refer a patient presenting with lice? (3)
1) Patient/caregiver has not seen a live louse or viable nit infestation (itching without being able to find anything is a problem)
2) Patient has had multiple treatment failures –> could indicate resistant strain
3) Presents with a secondary infection
What are the goals of therapy for treating a lice infestation?
1) exterminate lice
2) relieve pruritus
3) Prevent secondary bacterial infections
4) prevent the spread of the infestation
What are the non-pharmacological management options for the treatment of lice?
DISCLAIMER: non-pharmacological options are generally only recommended adjunctively
- environmental cleaning is generally not warranted
- avoid sharing personal items
- identify and examine the potential contacts
- mechanical removal via wet combing (every 3-4 days for 2 weeks)
- AirAlle/LouseBuster –> limited evidence points to efficacy but we cannot really recommend according to that
What is the gold standard pharmacological treatment for lice infestations? List the brand, age appropriateness, general application, AEs and cure rate.
Permetherin 1% cream –> brand: Kwellada-P, Nix
As per Canadian clinical standards, safe for use in >2 months
Application instructions:
- wash hair with conditioner free shampoo
- rinse with water and towel dry hair
- apply ~25-50mL to saturate hair and scalp
- leave on for 10 minutes
- rinse hair thoroughly with cool water and towel dry
- repeat in 7 days
AE: mild transient itching, redness, burning sensation of scalp, avoid in patient with chrysanthemum allergy
Safe in pregnancy
96-100% cure rate
What is the other topical insecticide used for lice infestations? List the brand, age appropriateness, general application, AEs and cure rate.
Pyrethrins 0.33%, Piperonyl butoxide 3.0% shampoo –> R&C Pronto
As per Canadian clinical standard guidelines, safe for >2 months
Instructions:
- apply to dry hair
- saturate hair and massage scalp/skin with >25mL of product
- leave for 10 minutes
- add water and lather and work into hair
- rinse with cool water and towel dry
- repeat treatment in 7 to 10 days
AEs: itchy or mild burning scalp, avoid in patients with allergy to ragweed and chrysanthemums
Safe in pregnancy
45-94% cure rate (first and second treatments respectively)
What is the most important counselling point when recommending a topical insecticide for the management of lice?
Itching after treatment is NOT a symptom of reinfection
If a patient is unsure of using an insecticide because they’re toxic, what should you tell them?
They don’t absorb through the skin and are safe to use
To minimize exposure elsewhere on the body, do not sit a child in the bath to rinse their hair
What are the product selection guidelines for picking a topical insecticide?
- preferred dosage form
- past medication experiences
- patient allergies and sensitivities
- convenience or desire for a single application
List the brand, age appropriateness, general application, AEs and cure rate for Dimeticone solution.
Dimeticone 50% is a non-insecticide –> Brand: Nyda
Can be safely used in >2 years of age
Instructions:
- saturate dry hair with spray and massage/comb into the hair
- after 30 minutes, comb with lice comb to remove dead lice and nits
- allow solution to dry on hair and for at least 8 hours
- wash out with regular shampoo
- repeat treatment in 8-10 days
AEs: less safety data than 1st line agents but no toxicity or resistance to date
97% effective; 100% ovoidal after 2 treatments
What is the MOA for Dimeticone/Nyda?
Solution flows into breathing systems of lice and nits, then thickens and suffocates them
List the brand, age appropriateness, general application, AEs and cure rate for Isopropyl myristate/cyclomethic one solution.
Brand: Resultz rinse
Clinical practice guidelines say safe in >4 years, package says >2 years
Instructions:
- saturate dry hair and scalp with product
- massage into scalp and leave for 10 minutes
- rinse with warm water
- repeat treatment in 7-10 days to kill new eggs
AEs: can stain clothing, less safety info than 1st line agents
57-93% effective after first and second application - NOT ovicidal
List the brand, age appropriateness, general application, AEs and cure rate for benzyl alcohol 5% lotion.
Brand: Ulesfia (most expensive option)
Safe for 6 months old to 60 years
Instructions:
- apply appropriate amount to dry hair and leave for 10 minutes
- rinse with water
- shampoo hair immediately
- remove dead lice with lice comb
- repeat in 7-9 days
AEs: expensive, well tolerated but may cause skin irritation, eye irritation, numbness, and decreased sensitivity, use in neonates has been associated with neonatal gasping syndrome
No effectiveness percentage given although it has no effect on nits
What are the treatment options to avoid for lice?
White vinegar –> may interfere with the efficacy of permethrin
Essential oils –> not supported for use in infants and children
Other NHPs –> no clinical evidence
Flammable liquids –> ineffective and may cause harm
What are the reasons that lice treatment may fail?
- misdiagnosis
- improper use of pedicullicide (not following instructions or repeating treatment)
- inadequate manual removal (needed in conjunction with pharmacologic treatment)
- repeated exposure/reinfestation
- resistance to pediculicide (rare)
What are some alternative Rx therapies for head lice?
Trimethoprim/topical permethrin 1% –> not approved in Canada for use against head lice (IMPORTANT: avoid in pregnancy)
Ivermectin –> 2 single doses 200ug/kg 7-10 days apart, not safe for under 15kg children
Ivermectin 0.5% –> not approved in Canada yet, similar efficacy to oral dosage
Permethrin 5% –> larger adverse effect profile, more itching after application
What are the treatments for pubic lice?
Same as head lice –> permethrin 1% or pyrethrins with piperonyl butoxide
If eyelashes are infested: remove nits with lice and tweezers, apply an occlusive non-medicated eye ointment like Lacralube
Sexual contacts within the previous month should be treated
Itching caused by the pediculocide can be treated with oral antihistamines or low-potency topical corticosteroid
What is the treatment for body lice?
Pediculicides are unnecessary, 1st line is simple hygienic measures:
- bathing and laundering if infested clothing and linens in hot water
- dry cleaning or storing the items in a sealed plastic bag for 2 weeks
If the lice are adherent to body hairs, pediculicides may be helpful
What are the reasons that nit policies should not be instituted?
- nits are not the carriers of disease
- nits may not even indicate an active infestation
- child would miss up to 14 days of school for no reason
- nits can persist after a successful treatment of crawling lice
- misdiagnosis is common
What are the safety and efficacy monitoring parameters to check for during follow up?
Efficacy: observe for any recurrence of lice/nits, if they persist after second application of product, patient should be advised to seek medical attention
Safety: any adverse effects, overuse should be discouraged, non-pharmacologic measures should be emphasized
What is the pharmacist’s role in the treatment of lice?
Provide information and dispel myths:
- lice infestations are common and do not indicate uncleanliness
- head lice infestations can be asymptomatic for weeks
- misdiagnosis is common; nits do not mean active infestation
- environmental cleaning and disinfection is not warranted
What is scabies and what are the risk factors?
Highly contagious parasitic skin infection caused by the mite Sarcoptes scabiei
Risk Factors:
- younger or older age
- immunocompromised or developmentally delayed
- overcrowded living conditions like nursing homes or jails
- bed-sharing
- close contact with infected individual
***can happen across all socioeconomic levels
How are the mites transmitted and how do they cause symptoms?
Mites spread through skin-to-skin contact
Adult female mites burrow into epidermis and deposit eggs which hatch in 2-4 days and mature from 10-14
Infected indiciduals experience a hypersensitivity reaction to mites, eggs and feces ~3 weeks after 1st exposure –> reaction occurs quickly upon reinfestation
What are the s/s of scabies?
- intense pruritus worse at night
- burrows, erythematous papules or vesicles
- usually >1 body area effected; face and scalp spared in adults
- scratching can lead to secondary infection
- stigmatization, depression and insomnia
What is crusted/Norwegian scabies?
Atypical, more contagious form of scabies that is most common in immunocompromised patients
Infestation may involve millions of mites
Lesions may smell and may not be itchy
High mortality rate due to secondary infection and sepsis
What is involved in the clinical diagnosis for scabies and how is this different from the definite diagnosis?
- history of pruritic rash that is worse at night and present in characteristic locations
- strengthened when similar symptoms are occurring in other household members
- burrows help to establish diagnosis
Definite diagnosis: skin scraping, burrow ink test, dermatoscopy; diagnosis should be made by an appropriate HCP prior to treatment
What are the goals of therapy for treating a scabies infestation?
1) eradicate mites
2) control symptoms
3) prevent complications
4) prevent spread
What are the non-pharmacologic strategies in the treatment of scabies?
- wash linens and clothes in soap and hot water using a HOT dry cycle
- all surfaces should be vacuumed
- avoid body contact with others until treatment and follow-up are complete
- trim fingernails to prevent injury from scratching
- cool compresses may help soothe itchy skin
What are the first line pharmacologic strategies for the management of scabies? What are their instructions, age appropriateness and cautions?
5% permethrin (Nix Dermal Cream, kwellada-P lotion)
- apply to all areas of the skin from the neck down in adults (30g/treatment, second bottle needed for second treatment)
- children head and neck should be treated
- leave on for 8-12 hours and repeat in 7 days
- safe for children >2 months
- choice in pregnancy and breastfeeding
- contraindicated in crysanthemum allergy
- may cause pruritis edema and erythema
Ivermectin oral (Rx –> stromectol)
- sincel 200ug/kg oral dose repeated in 2 weeks
- take with food to increase bioavailability and concentrations to the skin
- safety not established for children <15kg
- safety not established in pregancy and breastfeeding
- off label use; may cause mild itching, urticaria or fever
What are the second line pharmacological options for the management of scabies? What are the instructions, age appropriateness and cautions?
10% Crotamiton –> Eurax Cream
- apply to all areas of skin from neck down
- repeat in 24 hours, do not wash off until 48 hours after last application
- possible 2nd line in pregnancy and breastfeeding
- resistance reported
- not recommended for dermatitis; may cause local irritation
- contains counter irritant
5-10% Sulfur –> compounded product, no brand name
- apply qHS for 5-7 days
- preferred for infants <2 months; 8% petrolatum applied and 3 days of treatment, lowest toxicity
- possible second line for pregnancy and breast feeding
- malodorous and messy, stains clothing, not commonly used
Who should be treated for scabies?
All symptomatic and asymptomatic household members and close contacts
When can children with a scabies infestation safely return to school?
The day after they complete their initial treatment series
What are the adjunctive pharmacologic therapies for persistent itching?
- oatmeal baths
- antihistamines
- topical corticosteroids
- oral steroids (rarely)
How long can the itching last after killing all mites and how does this effect the monitoring plan?
Several weeks –> should be resolved within 4 weeks
