[Skin signs associated with epidermal growth factor inhibitors].
BACKGROUND: Inhibitors of epidermal growth factor receptors (EGFR) constitute a new alternative treatment for patients presenting certain advanced stage solid cancers (bowel, breast, ovary). Adverse cutaneous effects of these drugs are now starting to be described. OBSERVATIONS: Our study involved 2 men and 2 women with no previous history of acne included in a treatment protocol comprising EGFR inhibitors. Mean age was 52 years. The primary cancers were breast, ovary, bowel and unidentified. The EGFR inhibitors used were gefitinib (ZD1839) (2 cases), carnetinib (Cl1033) and cetuximab (IMC-C225). Skin lesions appeared after 7 days and included erythematous papules and follicular pustules of the face, back and upper chest. No comedons were seen, and there were no nodules or cysts. The severity of the rash resulted in discontinuation of treatment in 2 patients with complete disappearance of skin lesions in both cases. In one patient, reduction of the dosage of gefitinib (IMC-C225) led to gradual resolution of the rash. Histological examination of papules and pustules concluded on an acute suppurative folliculitis. Smears and cultures ofa nasal lesion and pustules revealed coagulase-positive Staphylococcus aureus in 2 patients. Combined doxycycline 100 mg daily and benzoyl peroxide was prescribed for 3 months and a favourable outcome was achieved after a mean 2 weeks. DISCUSSION: EGFR inhibitors act by inhibiting mechanisms oftumour proliferation in certain cancers at advanced stages or refractory to other treatments. Our findings in these four patients are similar to the published cases in terms of rapid onset of monomorphous, papulopustular, follicular eruption without comedons. Rapid response to cyclines and benzoyl peroxide is also reported in literature. This treatment must be instituted rapidly and patients must be informed about the cutaneous side-effects of EGFR inhibitors before the start of therapy. The pathophysiology of these eruptions is still unknown. Skin signs are probably due to interaction with EGFR functions, including overexpression of EGFR in keratinocytes and hair follicles.