Density of <i>Demodex folliculorum</i> in Patients Receiving Epidermal Growth Factor Receptor Inhibitors

Abstract

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.

Erosive Pustular Dermatosis of the Scalp-Like Eruption due to Gefitinib: Case Report and Review of the Literature of Alopecia Associated with EGFR Inhibitors

“…The mechanism of acneiform eruption is not fully understood. A topical metronidazole- or nadifloxacin-containing ointment is effective for acneiform eruption [4], and patients treated with EGFR inhibitors have an increased susceptibility to Demodex folliculorum colonization or infection [5], which supports the recent concept that EGFR inhibitors may induce an impairment of antimicrobial defense mechanisms [5]. Although acneiform eruptions can also be observed on the scalp in some patients and the intensity or severity can fluctuate, many lesions improve over time without discontinuation of the EGFR inhibitor [3].…”

<i>Demodex </i>Mites – Commensals, Parasites or Mutualistic Organisms?

“…The role of suppression of the host immune response in the facilitation of mite proliferation is suggested by the studies cited above and the publication by Gerber et al [19] in this issue.…”

“…In this issue, Gerber et al [19] introduce a new clinical setting in which Demodex numbers were found to be increased. In their retrospective study these authors demonstrated increased numbers of D. folliculorum in the cheek region of patients presenting with papulopustular lesions induced by epidermal growth factor receptor inhibitor following therapy for cancer.…”

Associations between Demodex species infestation and various types of cancer

“…Several factors could allow proliferation of Demodex species to this critical level. The role of suppression of the host immune response in the facilitation of Demodex proliferation is suggested (Gerber et al 2011), and it has been reported that a hyporesponsiveness status may be associated with an increase in the density of D. folliculorum and demodicidosis in children with leukemia who are receiving chemotherapy (Patrizi et al 1997, Damian andRogers 2003).…”