Vol 10, Nbr 10 - International Journal of Pharmaceutical Compounding

SA
MP
LE
VO L U M E 1 0
NUMBER 10
Schools Back! (And So Are Lice Infestations)
Loyd V. Allen, Jr., PhD, RPh
International Journal of Pharmaceutical Compounding
Edmond, Oklahoma
Introduction
Lice infestations (Pediculosis) are a parasitic infestation of the skin of the scalp (head lice), trunk (body
lice), and pubic areas (crab lice). Lice are small, wingless parasites with reasonably well-developed legs. Lice
infestations are common among all social groups in the U.S., affecting about 10 million Americans annually.1,2 Their infestation appears to be at its height in children a few weeks after school starts each fall (August
through November), after extended vacations, and right after camps. They are also common in daycare
centers and nursing homes.1,2
Children are more likely than
adults to acquire the infection, and
preschoolers are at the highest risk.
Girls tend to get infected at a higher
rate then boys and whites get infected at higher rates than blacks.1,2
Source of Infection
Head lice are commonly transmitted
by shared use of caps or combs and
are epidemic among children of all
socioeconomic levels, especially in
elementary schools. Adults with head
lice almost always acquire the infection from school-age children. Body
lice generally occur among those
living in overcrowded dwellings with
inadequate hygiene facilities. Pubic
lice can be acquired by sexual transmission, shared toilets, etc.
Three different varieties of lice are
generally involved: (1) Pediculus
humanus var capitis (involved with
head lice), (2) Pediculus humanus var
corporis (involved with body lice),
and (3) Pthirus pubis (involved with
pubic lice or “crabs”).1
The head and body lice are very
similar in appearance and are about
3 to 4 mm long; with the body
louse being larger. Head lice can be
observed on the scalp, but body lice
are seldom observed on the body;
generally they are on the clothing or
in the seams of clothing and only go
to the body to feed.
Infestations of body lice often occur in individuals that do not change clothing frequently, such as the homeless, as well as in soldiers in extended military campaigns. The body louse can also transmit trench fever,
relapsing fever, and typhus, where these diseases are endemic.
The pubic louse, commonly called a crab louse because of
their crab-like appearance, can be encountered in all levels of
society. It is evidenced by the presence of the parasite, and its
nits are generally in the pubic area. Pubic louse infestations
may actually be generalized, especially in hairy individuals,
and the lice can also be found on the eyelashes, eyebrows,
mustaches, beards, and in the scalp.
SA
MP
LE
Clinical findings with head lice involve itching, and the lice
can be observed crawling or as small nits attached to a hair
shaft, resembling a bud on a leaf, close to the skin, especially
above the ears and on the nape of the neck. It is actually difficult to observe a crawling head louse. Body louse infestations
include symptoms of itching and associated scratching which
may result in excoriations, especially over the upper shoulders,
backside, and neck. Pubic louse symptoms also include itching.
The itching in these lice infestations results from the bite of
a louse that causes an immediate wheal to develop around the
bite. Lice may feed up to five or six times daily. If itching is
severe, subsequent scratching may result in excoriation and/or
secondary pyogenic infection.
Treatment
The goals of treatment include ridding the infested patient
of the lice and preventing future lice infestations by avoiding
direct physical contact with infested individuals and personal
items (combs, brushes, towels, caps, hats).
Treatment of louse infestations is difficult due to the ease of
spreading the problem. Individuals can generally be effectively
treated but then upon exposure become re-infected. Over the
years, this has resulted in resistance to the permethrins and a
search for new treatment alternatives for louse infestations.
Malathion remains a widely used compounded treatment,
and, recently, ivermectin has been prescribed for this.2-4 The
general treatment regimens are as follows:1-4
Head Lice:
• Apply ivermectin 0.8% lotion; leave on for up to 8 to 12
hours before rinsing off.
• Apply malathion 0.5% or 1% lotion to scalp; leave on for
up to 12 hours.
• Apply permethrin 1% cream; leave on for 30 minutes to 8
hours before rinsing off. (Repeat treatment in one week.)
Note: Permethrin 5% lotion can be used in refractory
cases.
• Apply pyrethrins 0.17% to 0.33%; repeat in 7 to 10 days to
kill lice larvae. Note: Do not apply more than twice in 24
hours.
General instructions for treating head lice: After application,
meticulously remove nits with a fine-tooth comb.
Body Lice:
• Apply ivermectin 0.8% lotion; leave on for up to 8 to 12
hours before rinsing off.
• Apply malathion 0.5% or 1% lotion; leave on for up to 12
hours.
• Apply permethrin 1% rinse; leave on for 10 minutes or
apply permethrin 5% cream; leave on for 8 hours.
• Apply pyrethrins 0.17% to 0.33%; repeat in 7 to 10 days to
kill lice larvae. Note: Do not apply more than twice in 24
hours.
General instructions for treating body lice: Avoid sexual
contact. Wash and dry clothes and and bedclothes at hot
temperatures.
Pubic Lice:
• Apply ivermectin 0.8% lotion; leave on for up to 8 to 12
hours before rinsing off.
• Apply malathion 0.5% or 1% lotion; leave on for up to 12
hours
• Apply ivermectin 0.8% lotion; leave on for up to 8 hours
before rinsing off
General instructions for treating pubic lice: Avoid sexual contact. Wash and dry clothes and bedclothes at hot temperatures.
General Considerations in
ment of Lice Infestations
the
Treat-
1. Use appropriate topical agent and treat ALL family members.
2. Use hot water to wash brushes, combs, and toys; dry items
with hot air.
3. Use hot water to wash clothing; dry with hottest dryer setting.
4. Seal any clothing that cannot be washed (coats, etc.) in
plastic bags for at least two weeks (the life cycle of a louse
when unable to feed on a host).
5. Schedule follow-up visit with physician, pharmacist, or
school nurse.
Prevention of Lice Infestations
1. Avoid direct physical contact with infested individuals.
2. Do not share personal articles, such as combs, brushes,
towels, hats, caps, etc.
Pediculicides
Ivermectin is a mixture of various components and occurs as
a white or yellowish-white, slightly hygroscopic, crystalline
powder. It is practically insoluble in water and soluble in
alcohol.4
Permethrin (C21H20Cl2O3, MW 391.3) is a pyrethroid
insecticide used as a 1% application in the treatment of head
lice. Permethrin is generally more effective than synergized
pyrethrins.4
Malathion (C10H19O6PS2, MW 330.4) occurs as a clear, colorless or slightly yellowish liquid that solidifies at about 3°C.
It is slightly soluble in water and miscible with alcohol and
vegetable oils. Lotions are generally preferred to shampoos
as the contact time is longer.4,5
Pyrethrins (Pyrethrin I and Pyrethrin II) occur as a viscous, brown, liquid oleoresin that is obtained from chrysanthemum flowers. They are practically insoluble in water and
soluble in alcohol. They can be absorbed through the skin.
Pyrethrins are used in concentrations from 0.17% to 0.33%
generally in combination with 2% to 4% piperonyl butoxide.
Dosage forms include solutions, shampoos, and gels.2,4
Compounded Formulations for Lice Infestations
Rx
Malathion 0.5% Topical Lotion
Rx
Ivermectin 1% Creme Rinse
Rx
Ivermectin 1% Lotion
Rx
Head Lice Repellant Spray
Note: This is a repellant spray and not a treatment.
Piperonyl butoxide (C19H30O5, MW 338.4) occurs as a yellow or pale brown oily liquid with a faint
characteristic odor. It is very slightly soluble in water and miscible with alcohol. It is used as a synergist for
pyrethrin and pyrethroid insecticides. Mixtures of pyrethrins and piperonyl butoxide are used in the treatment of lice infestations.4
References
1. Tierney LM Jr, McPhee SJ, Papadakis MA. Current Medical Diagnosis and Treatment. 41st ed. New
York: Lange Medical Books/McGraw-Hill; 2003: 130–133.
2. Pray WS. Nonprescription Product Therapeutics. 1st ed. Baltimore, MD: Lippincott Williams &
Wilkins; 1999: 462–469.
3. Mumcuoglu KY, Miller J, Rosen LJ. Systemic activity of ivermectin on the human body louse (Anoplura: Pediculidae). J Med Entomol 1990; 27(1): 72–75.
4. Sweetman SC. MARTINDALE: The Complete Drug Reference. 33rd ed. London, UK: Pharmaceutical Press; 2002: 99–101, 1434–1436.
5. Glasnapp A, Linh N. Malathion topical lotion: Therapy for resistant head lice. IJPC 1998; 2(4):
268–269.
RxTriad-A publication of the International Journal of Pharmaceutical Compounding. © 2007 IJPC. All rights reserved.