Folliculitis and perionyxis associated with the EGFR inhibitor erlotinib

Epidermal growth factor receptor (EGFR) is widely expressed in the skin, and therefore, cutaneous side effects are not surprising in the context of systemic EGFR inhibition. Indeed, skin adverse reactions are the most frequent side effects observed with these drugs. This case report is typical of the cutaneous side effects observed with EGFR inhibitors, i.e., folliculitis and perionyxis. A 68-year-old patient was treated with 150 mg of erlotinib for a stage-IIIb nonresectable non-small cell lung carcinoma (T4NXM0) as first-line chemotherapy. One week later, he presented with a papulopustular follicular rash on his face and trunk, which rapidly worsened over the following weeks. Doxycycline was prescribed, and the cutaneous lesions improved although erlotinib treatment was continued. Further on in the treatment, the patient presented a relapse of the cutaneous folliculitis along with painful perionyxis, with an appearance of pyogenic granulomas surrounding several toenails and fingernails. Erlotinib treatment was withdrawn and an additional course of tetracycline was prescribed, associated with local antiseptic treatment on the face, and silver nitrate on the perionyxis. One week later, the cutaneous lesions had greatly improved and erlotinib was reintroduced. The patient's lung tumor was stabilized for 10 months under the therapy. Clear information regarding skin-related side effects should be given to the patients before treatment onset. Physicians also have to adapt the management of these cutaneous side effects to the context of long-term prescriptions of these new drugs. Because folliculitis severity is now recognized as a surrogate marker for treatment efficacy, exploration of the connection between skin reaction and tumor response opens the way for new challenging research perspectives.