Simple tools provide quick, accurate diagnostics for bedside and beyond

Whether in a resource-poor area overseas or at the bedside in a tertiary care hospital in your clinic, with just a few tools you can quickly diagnose a host of diseases ranging from chicken pox to scabies, said Karolyn Wanat, MD, director of the session “Beyond the Tzanck: Bedside Diagnostics for Dermatologists,” presented Friday.

“Our training as dermatologists focuses on visual diagnosis and then confirming or further diagnosing under the microscope,” Dr. Wanat, assistant clinical professor of dermatology at University of Iowa Hospitals and Clinics, Iowa City, said in an interview before the session. “We thought expanding the tools that we have at our disposal to other areas or other diseases could be really powerful.”

The session focused on basic techniques: the Tzanck smear, the potassium hydroxide (KOH) preparation, Gram stain, and the mineral oil preparation. The techniques can diagnose molluscum contagiosum; herpetic infections; hand, foot, and mouth disease; tinea; bacterial folliculitis; and botryomycosis, to name a few.

The Tzanck smear, named for French dermatologist Arnault Tzanck (1886-1954), aids in the diagnosis of herpetic lesions, autoimmune blistering disorders, cutaneous malignancies, and other infectious processes. The KOH preparation is used to diagnose fungal and yeast infections. The mineral oil preparation diagnoses ectoparasitic infestation and is especially useful for diagnosing scabies, which enables rapid initiation of therapy, and for diagnosing rosacea related to Demodex.

The speakers discussed the best techniques for getting the most out of each test. “Although it seems simple when you describe it — you have a lesion on the skin, you scrape it, smear it on a slide, and then look at it under the microscope,” Dr. Wanat said, “it is a skill for which there are some tricks about where you take the sample from and how you can process the sample that can help improve diagnostic results.”

The session, which was new to the Annual Meeting, also discussed the requirement for CLIA (Clinical Laboratory Improvement Amendments) certification and standards for laboratories.

The speakers were Dr. Wanat, Robert Micheletti, MD, assistant professor of dermatology at the University of Pennsylvania Perelman Center for Advanced Medicine, Philadelphia, and Arturo Dominguez, MD, assistant professor of dermatology at University of Texas Southwestern Medical Center, Dallas. They are collaborating on an article on the topic.

“All three of us are involved in and love in-patient consults,” said Dr. Wanat. “Oftentimes these patients are sick, so by performing a bedside diagnostic test, we can come up with a diagnosis earlier and potentially implement treatment earlier.”

The tests also can be invaluable in global health, said Dr. Wanat, who has done dermatology work in Botswana through AAD.

“These are tools available to dermatologists to enhance patient care, expedite treatment, and even potentially save some health care costs,” said Dr. Wanat. “The tests are relatively inexpensive. The materials needed are inexpensive and can last a long period of time.”

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