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Presentation

Dermatologic Infections in the Immunocompromised: Diagnosis and Management in Iatrogenic Immunosuppression and HIV

Description

The talk reviewed how to diagnose and manage skin infections in immunocompromised patients, emphasizing that clinicians must consider both the lesion’s morphology and the patient’s immune background. It focused on iatrogenic immunosuppression and HIV. For patients on TNF-alpha inhibitors and other biologics, the speakers explained the infection risks associated with each drug class, with TNF blockade particularly predisposing to granulomatous infections such as mycobacteria and fungi, while JAK inhibitors increase zoster risk and anti-CD20 agents raise the risk of many infections, especially hepatitis B. A Crohn’s disease case highlighted a sporotrichoid eruption after salt-water exposure; initial biopsy and culture were negative, but broad-range PCR identified Mycobacterium marinum, and the patient improved with azithromycin and rifampin. The discussion then turned to HIV, explaining that immune status is best assessed with viral load, CD4 count, and sometimes CD4 percentage during acute illness because transient lymphopenia can lower the absolute CD4 count. Morphology-based diagnosis was stressed for umbilicated papules in HIV, using the mnemonic CHIMP to consider cryptococcosis, histoplasmosis, molluscum contagiosum, mpox, and talaromycosis. Bedside diagnostics such as India ink, Giemsa, and zinc smear were reviewed. The HIV case was ultimately molluscum contagiosum, managed mainly with antiretroviral therapy and observation, with improvement over time. The talk concluded that if cultures are negative but suspicion remains high, broad-range PCR and next-generation sequencing can be very useful, and in stable non-tuberculous mycobacterial infection, treatment is often best delayed until species identification is available to avoid resistance.

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Conclusions

TNF-alpha inhibitors substantially increase the risk of granulomatous infections, especially mycobacterial and fungal diseases, while also raising risk for some bacterial and viral infections.
The specific infection risk from biologic therapy depends not only on the drug class but also on the underlying disease being treated and the timing of exposure.
When a sporotrichoid eruption occurs in an immunocompromised patient, exposure history is critical for narrowing the differential, but staph and strep remain the most common causes overall.
If cultures are negative but suspicion for cutaneous infection remains high, broad-range PCR and next-generation sequencing can identify pathogens such as Mycobacterium marinum.
For stable suspected nontuberculous mycobacterial skin infections, waiting for speciation and susceptibilities is preferred because resistance patterns vary by species.
In HIV, immune status is best interpreted using viral load, CD4 count, and sometimes CD4 percentage during acute illness rather than relying on morphology alone.
Umbilicated papules in advanced HIV most strongly suggest cryptococcosis, histoplasmosis, molluscum contagiosum, mpox, or penicilliosis/talaromycosis.
Morphologic clues and bedside tests can rapidly distinguish opportunistic infections in HIV and guide urgent diagnosis and treatment.
Severe mpox appears to be associated with uncontrolled HIV, delayed antiviral treatment, and signs of necrotizing disease such as acral cutaneous necrosis and facial edema.
In some opportunistic infections in HIV, starting antiretroviral therapy and allowing time for immune recovery can lead to improvement even without aggressive lesion-directed therapy.
Imiquimod is often less effective for extensive molluscum in uncontrolled HIV because an intact T-cell response is needed for it to work.
Overall, the presentation emphasizes that successful management of skin infections in immunocompromised hosts requires integrating host immune status, exposure history, lesion morphology, and targeted diagnostic testing.

Jacobs M, et al. Microbes Infec 2007.
Casto A, et al. Blood Rev 2022.
An Official ATS/IDSA Statement: Diagnosis, Treatment, and Prevention of Nontuberculous Mycobacterial Diseases (2006/2007).#10.1164/ajrccm.175.7.744b
Li S. et al., Front Immunol 2022.
Srivastava G, et al. BMJ Case Rep 2015.
Azar M, et al. Am J Trop Med Hyg 2016.
Wanat K, et al. J Am Acad Dermatol 2017.
Cao C, et al. Mycopathologia 2019.