Bugs, Resistance, and What’s Next: Infectious Disease Intel for the Busy APP

At Dermatology Week APP Day 2025, Ted Rosen, MD, delivered a rapid-fire update that kept attendees scribbling notes—and raising eyebrows. His session, “What APPs Need to Know Now About Cutaneous Infections,” spotlighted the newest threats, resistance patterns, diagnostic blind spots, and therapeutic options dermatology providers need to keep on their radar.

Dr Rosen kicked things off with a look at impetigo and how go-to therapies like mupirocin may be losing ground. Global resistance rates hover around 10%, and in some hotspots, such as Miami, nearly 1 in 4 methicillin-resistant Staphylococcus aureus (MRSA) isolates no longer respond. He encouraged attendees to be aware of local resistance patterns and introduced ozenoxacin, a topical quinolone, as a potential alternative, although access remains limited due to cost and specialty pharmacy requirements.

He moved on to oral antibiotics, noting that MRSA resistance to doxycycline and TMP-SMX is on the rise nationwide, making once-reliable therapies less dependable.

From there, Dr Rosen transitioned into infectious disease cases that doubled as diagnostic challenges, such as a patient with fever and eschar after a tick bite in Missouri. The culprit? Tularemia, a condition more common in the Midwest than many clinicians realize.

Dr Rosen revisited the changing map of Lyme disease, which now extends far beyond the Northeast and upper Midwest. He flagged early doxycycline failure rates (up to 20%) and shared encouraging news about a promising vaccine candidate (VLA15) now in phase 3 trials.

Tuberculosis also earned a mention, not for its pulmonary effects but for its cutaneous presentations, which Dr Rosen emphasized are diverse and increasingly relevant as case numbers rise in states like California, Texas, New York, and Florida.

“We can’t talk about viruses without talking about [herpes simplex virus] HSV1 and HSV2,” Dr Rosen said, reminding attendees that acyclovir resistance is real, especially among immunocompromised patients.

He highlighted pritelivir mesylate, a helicase-primase inhibitor currently available under expanded access for patients with severe, treatment-resistant HSV.

Dr Rosen flashed through re-emerging viral threats—Chikungunya, Oropouche, and Zika—with new outbreaks reported in Brazil, Paraguay, India, and Cuba. He recommended the Vimkunya vaccine (currently the only available option for Chikungunya) for travelers to endemic regions.

He also delivered a stark update on dermatophyte resistance, particularly Trichophyton indotineae, now circulating globally with high rates of terbinafine and itraconazole failure. While culture and sensitivity testing is hard to obtain, he offered a surprising back-pocket solution: Whitfield’s ointment, an old-school combination of salicylic and benzoic acid that works by simply peeling the fungus away.

Looking ahead, he flagged olorofim, a novel antifungal in development that may offer new hope for resistant cases.

Dr Rosen closed with a word on ectoparasites such as scabies, including increasing resistance to permethrin and ivermectin. He pointed to spinosad, a US Food and Drug Administration-approved treatment for lice now being used off-label for scabies with high cure rates.

“I hope I haven’t scared you too much,” Dr Rosen quipped at the end. “Remember, knowledge is power.”

For more meeting coverage, visit the Dermatology Week APP Day newsroom.

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Reference

Rosen T. What APPs need to know now about cutaneous infections. Presented at: Dermatology Week; October 22–25, 2025; Virtual.