The Journal of the Arkansas Medical Society Med Journal Feb 2020_Final | Page 4

derm dilemma
A
Special Section: Short Dermatological Cases
by Kyle Sandiford, MD candidate, Class of 2021
Logan Rush, MD, Resident, UAMS Dept of Dermatology
Kevin St. Clair, MD
20-year-old college student presents
with a widespread, intensely pruritic
rash which has progressively wors-
ened over the past two months. It is
located diffusely on her body, but is most promi-
nent in her axillae, areolae, waist, and interdigital
web spaces. The primary eruption appears to be
small, 2-3mm excoriated papules. Using a #15
scalpel blade and mineral oil, scrapings were
taken of a few of the papules of the interdigital
web spaces and examined with light microscopy
(see Figure 1).
What is the next most
appropriate step?
A) Topical triamcinolone ointment twice
daily x 10 days
B) Praziquantel 20 mg/kg PO three times
daily x1 day only
C) Permethrin cream 5% applied from
the neck down, and repeated in 7
days
D) Punch biopsy of an intact papule, as
the scraping was not diagnostic
E) Examination of the seams of clothing
for live lice (Pedicululus humanis
corporis) or nits (eggs)
Answer: C
The photomicrograph above demonstrates the
human-specific mite Sarcoptes scabiei homi-
nis (dark oval structure upper right of photo).
Scabies can have variable clinical presentations,
but often presents as pruritic excoriated pap-
ules most prominent in the interdigital spaces,
flexural creases, areola of women, glans penis,
and volar wrists. While observation of bur-
rows (thread-like linear elevations of a few mm
length that represent the intraepidermal tunnel
152 • The Journal of the Arkansas Medical Society
Figure 1.
resulting from the burrowing of female mites)
is highly suggestive of an infestation, definitive
diagnosis requires direct observation of mites,
eggs, or scybala (feces) on a prepared slide.
When a burrow is located on the skin, a drop of
mineral oil is placed over the area, followed by a
superficial longitudinal scraping motion utilizing
a surgical blade. Mite eggs are also observed
in the photomicrograph above (small oval struc-
tures bottom left).
of choice; crotamiton and precipitated sulfur in
petrolatum are alternative topical agents. Oral iv-
ermectin may also be prescribed. It is important
to inform patients that the pruritus may persist
for several weeks after scabicidal treatment. •
Therapy should be given simultaneously to
household and sexual contacts of the infested
patient, and clothing and bedding used in the pre-
vious several days should be washed in hot water
or sealed in a plastic bag for 3 days. Scabies mites
generally cannot survive for more than 3 days off
of a human host. Currently, topical permethrin
5% cream (repeated in 7 days) is the treatment
Arkmed-pac
needs you in 2020
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