Density of Demodex folliculorum in patients receiving epidermal growth factor receptor inhibitors.

BACKGROUND

Rosacea-like papulopustular eruptions (rash) are considered the most frequent toxicities associated with the use of inhibitors of the epidermal growth factor receptor (EGFR). Recently, evidence has been accumulating of infectious complications in patients suffering from these adverse effects.

OBJECTIVE

We sought to analyze the density of Demodex folliculorum (DF) in cutaneous lesions of patients presenting with EGFR-inhibitor (EGFRI)-induced rashes.

METHODS

This is a retrospective study of 19 adult patients presenting with EGFRI rashes. Patients were reviewed for the density of DF (Demodex density, Dd; mites per square centimeter) by standardized skin surface biopsy.

RESULTS

In our patient collective the mean Dd of 4.7/cm² significantly exceeded the mean Dd reported for the healthy adult population (Dd = 0.7/cm²).

LIMITATIONS: The retrospective nature of the study.

CONCLUSIONS

EGFRI patients have an increased susceptibility to DF colonization or infection, respectively. Our results support the recent concept that EGFRI may induce an impairment of antimicrobial defense mechanisms.