TOPLINE:

In a study, 5.5% of patients developed demodicosis within 100 days of a hematopoietic cell transplant (HCT); oral ivermectin was effective, with some reports of Mazzotti-like inflammatory reactions.

METHODOLOGY:

• Researchers conducted a retrospective cohort study of 307 patients who underwent allogeneic HCT at the National Institutes of Health between January 2016 and August 2023.
• Overall, 17 (5.5%) patients were diagnosed with demodicosis within 100 days of allogeneic HCT.
• Treatment involved administration of oral ivermectin at 200 μg/kg weekly doses for 15 patients, with clinical response and adverse reactions monitored.

TAKEAWAY:

• Demodicosis typically presented as erythematous, pruritic folliculocentric papules, or papulopustules on the sebaceous skin of the face, neck, and upper trunk, occurring at a median of 32 days post-transplant and a median of 18 days after neutrophil engraftment. In 12 of 15 patients who had a documented scalp exam, the hair-bearing scalp was spared, and relative sparing of periocular skin was observed in 15 patients.
• Nine patients (53%) developed acute cutaneous graft-vs-host disease either concurrently (67%) or sequentially (33%) with demodicosis onset.
• Diagnostic testing was supportive: Potassium hydroxide scrapings were positive for mites in 14 of 14 tested patients, and biopsy findings were consistent in 12 of 12 tested patients.
• Ivermectin led to clinical improvement in treated patients, but four developed an inflammatory Mazzotti-like reaction within 1-5 days, marked by facial edema and systemic symptoms; patients who experienced these reactions had a significantly longer median time to rash resolution (32 vs 7 days; P = .03).

IN PRACTICE:

“In this post-HCT population, demodicosis was a cause of folliculocentric facial eruptions” and “should be considered in the differential diagnosis for post-HCT facial eruptions,” the authors of the study wrote. “While oral ivermectin is effective for demodicosis,” they added, “it may cause a Mazzotti-like reaction characterized by facial edema and systemic symptoms.”

SOURCE:

The study was led by Jennifer Strong, MD, Dermatology Branch, National Institutes of Health, Bethesda, Maryland, and was published online on December 3 in JAMA Dermatology.

LIMITATIONS:

The study is limited by its retrospective single-center design, small cohort size, and the lack of validated diagnostic tests for demodicosis.

DISCLOSURES:

This research was supported by the National Institutes of Health Intramural Research Program and the National Institutes of Health Medical Research Scholars Program. The authors reported having no relevant conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.