Scalp Pustule as a Manifestation of Erlotinib-Induced Skin Toxicity: Report of Two Cases and Literature Review.

INTRODUCTION

Erosive pustular dermatosis of the scalp (EPDS) is a rare, chronic inflammatory disorder characterized by sterile pustules, erosions, crusting, and scarring alopecia, which has been occasionally reported in association with epidermal growth factor receptor inhibitors (EGFRIs).

METHODS

We report two cases of EPDS induced by erlotinib therapy for non-small cell lung cancer (NSCLC). Case 1 involved a 73-year-old female with four years of erlotinib use presenting with scalp pustules, alopecia, and scarring. Case 2 was a 37-year-old male who developed papulopustular lesions on the scalp and trunk after six months of erlotinib therapy. Histopathological examination was performed on biopsy samples from both EPDS patients and compared with samples from two healthy controls.

RESULTS

Comparative analysis revealed neutrophilic infiltration, irregular epidermal hyperplasia, and elevated EGFR expression in hair follicles and epidermal keratinocytes in EPDS patients versus controls. These findings demonstrate how EGFR inhibition disrupts keratinocyte function and triggers inflammatory responses leading to severe follicular damage.

CONCLUSION

These cases highlight the importance of dermatological monitoring in patients undergoing EGFRI therapy. Early recognition and management with antibiotics and topical steroids may help mitigate adverse effects. Further research is needed to elucidate underlying mechanisms and optimize treatment strategies for EPDS.