Master the board step 3

Dermatology
Paronychia
This is an infection loculated under the skin surrounding a nail.
It is generally treated with a small incision to allow drainage and antistaphylococcal
antibiotics as previously described.
Viral Infections
Herpes Simplex
Herpes simplex infections of the genitals are characterized by multiple, painful
vesicles. They are usually obvious by examination, and you should proceed
directly to therapy with acyclovir, famciclovir, or valacyclovir.
Diagnostic Testing
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Best initial test: In the event that the diagnosis is not clear or the lesions have
become confluent into an ulcer, then the best initial test is a Tzanck smear.
The Tzanck smear is somewhat nonspecific in that it will only determine that
the infection is in the herpes virus family. Tzanck smears detect multinucleated
giant cells and are similar in technique to a Pap smear. A scraping of the
lesion is immediately placed on a slide and sprayed with fixative.
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Most accurate test: Viral culture. This grows in 24–48 hours.
Treatment
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Oral acyclovir, famciclovir, or valacyclovir
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Topical acyclovir has extremely little efficacy.
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Topical penciclovir has some utility for oral herpetic lesions, but it must be
used every 2 hours.
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The treatment of acyclovir-resistant herpes is with foscarnet.
The most common
wrong answer is serology.
Serology is not a useful
test for diagnosing acute
herpes infections.
Herpes Zoster/Varicella
Chickenpox is primarily a disease of children. It is generally not treated with
antivirals. If the child is immunocompromised or the primary infection occurs
in an adult, then acyclovir, valacyclovir, or famciclovir should be given.
Complications of varicella are the following:
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Pneumonia
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Hepatitis
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Dissemination
Outbreaks of shingles, also known as dermatomal herpes zoster, occur more
frequently in the elderly and those with defects of the lymphocytic portion of
the immune system, such as leukemia, lymphoma, or HIV, or those on steroids.
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