small punctures they make through the skin. Lice
attach their eggs, called nits, to HAIRshafts. Of the
numerous species of lice, three afflict humans:
- Pediculus humanus capitis, which infests the scalp
- Pediculus humanus corporis, which infests the
body - Pediculus pubis, which infests the pubic region
Each species has unique claw and MOUTHstruc-
tures that allow survival in the particular region of
the body, and each species can infest only the
body region for which it is adapted. However,
infestation with two or more species is common.
Pediculosis refers collectively to infestation with
any species of lice, and affects around 12 million
Americans each year.
Pediculosis spreads easily through direct and
indirect contact, and is so common among school-
age children that schools routinely screen for its
presence. Crowded environments, such as schools
and dormitories, allow close contact between peo-
ple, permitting the lice to spread from one person
to another. Pediculosis may be present for as long
as two months before causing appreciable symp-
toms, increasing the potential for extending infes-
tation. Head and pubic lice and nits resist the most
scrupulous cleansing. Infrequent clothing changes
are often a factor with body lice infestation. Poor
PERSONAL HYGIENEsuch as infrequent bathing can
allow secondary problems such as INFECTION to
develop.
Symptoms and Diagnostic Path
The most common symptom of pediculosis is itch-
ing, which is often particularly intense at night
when the lice feed. The saliva of the lice contains
enzymes to delay coagulation (blood clotting)
which irritate the skin. The bites leave reddened
papules (raised bumps) that continue to itch.
Finding nits (eggs attached to hair shafts) is the
conclusive diagnostic marker. Nits are difficult to
remove, which helps distinguish them from other
matter that might collect on the skin or hair, as
well as from conditions such as seborrheic DER-
MATITISand common DANDRUFF. Examination with
fluorescence (Woods lamp) causes the lice and nits
to glow yellow or green.
Treatment Options and Outlook
Treatment for head or pubic infestation combines
removing the nits with a fine-tooth comb (nit
comb) and shampooing or washing with an insec-
ticide-based product such as permethrin (Nix) or
malathion (Ovid). Multiple treatments about a
week apart for a month, or until no nits are pres-
ent, are necessary to cover the lifespan of the
louse, which is about 35 days. It is important topediculosis 181CHARACTERISTICS OF PARONYCHIA
Acute Chronic
symptoms PAIN, redness, and swelling tenderness and swelling of the skin around the nail
SKINaround the nail appears tight and bright redness and increased discomfort with prolonged
red exposure to water (such as washing dishes)
may have pus ongoing for longer than four to six weeks
precipitating trauma (sliver, pulled hangnail, repeated exposure to water, chemicals, other irritants
biting the nail or skin) discolored or thick nail on the affected finger or toe
sudden onset separation of the cuticle from the nail bed
infective agent Staphylococcus aureus Candida albicans
Streptococcus
Pseudomonas
medication oralANTIBIOTIC MEDICATIONSsuch as topical antifungal medication such as miconazole
clindamycin, cephalexin, or amoxicillin and oral antifungal medication such as ketoconazole or
clavulanic acid fluconazole