Erlotinib-Induced Trichomegaly of Eyelashes in Lung Cancer Treatment: Epidermal Growth Factor Receptor Inhibitor Side Effect

Erlotinib, an epithelial growth factor receptor tyrosine kinase inhibitor used in treating non-small cell lung cancer, can cause rare side effects such as eyelash trichomegaly. This report details a case in a nonsmoking woman with lung adenocarcinoma who developed significant eyelash overgrowth and vision problems after several months of erlotinib therapy. Dermoscopy showed increased eyelash length and thickness with eyelid inflammation. The inhibition of epithelial growth factor receptor signaling may alter hair growth patterns, leading to trichomegaly, a side effect documented in only a few cases.