EGFR inhibitor-induced skin reactions: differentiating acneiform rash from superimposed bacterial infections

Purpose: Epidermal growth factor receptor (EGFR) inhibitors are approved for use as targeted chemotherapeutic agents against multiple solid-organ malignancies. The most common side effect associated with EGFR inhibitor therapy is a papulopustular eruption, which can easily be confused with bacterial folliculitis. In this study, we examine the relative timing and location of the EGFR-induced papulopustular eruption compared to the associated bacterial superinfections. Methods: In this retrospective chart review, patients enrolled in our institution’s IRB-approved prospective registry of cutaneous reactions to chemotherapy were screened for inclusion. All patients who received an EGFR inhibitor and developed either a papulopustular eruption or bacterial superinfection at some point during treatment were included. Results: Of the 157 patients who met inclusion criteria, 36 (23 %) developed bacterial superinfections at some point during EGFR therapy. Papulopustular eruptions developed in a highly predictable time course, with a mean time to onset of 1.5 weeks and mean duration of 9.4 weeks. Bacterial superinfections occurred at widely variable time points during therapy with a mean time to onset of 27.7 weeks. Papulopustular eruptions much more frequently affected the face (97 %), chest (75 %), and back (61 %), while bacterial superinfections occurred more commonly on the upper extremity (64 %), lower extremity (47 %), and abdomen (39 %). Conclusions: The EGFR inhibitor-induced papulopustular eruption has a stereotypical time course and occurs in a characteristic distribution affecting the central face, upper chest, and back. Bacterial superinfections more frequently affect the extremities, abdomen, and groin and may occur at any point during EGFR therapy.