Assessing clinical and morphological features of megalotrichosis induced by Tyrosine kinase inhibitors versus Prostaglandins analogues

Purpose Describing the features of Megalotrichosis (MT) induced by Tyrosine kinase inhibitors (TKI) and differentiate it from Prostaglandins (PGs)–induced MT. Methods Medical data of patients with MT referred to our center between 2012–2021 were retrieved for: demographic parameters, medical, surgical and oncologic background, and ophthalmologic background along with diagnoses and treatment. Time from PGs/TKI introduction to MT presentation, MT clinical characteristics, associated complaints, and prescribed therapies in relevant cases were also documented. Ophthalmologic exam, ocular photography and data retrieved from medical records were used to assess MT features among the two groups. Morphological evaluation included number of upper (UL) and lower lid (LL) eyelash rows, poliosis, individual elongated eyelash and eyelash curvature. Masked evaluation of all the patients was performed. Results We found 11 patients, of which 6 treated with PGs for glaucoma and 5 treated with TKIs for non-ocular cancer suspected of dissemination. TKIs-induced MT was characterized by more individual elongated eyelashes (p = .047), UL eyelash rows (p = .03) and eyelash curvature (p = .076); poliosis characterized PGs-induced MT (p = .076). MT-associated complaints were more frequent in TKIs-induced MT (p = .06). time from drug administration to MT onset was shorter with TKI compared to PGs (median 176 Vs. 440 days, p = .257). Conclusions The study suggests that TKI-induced MT presents faster than PGs-induced MT and might be more bothering to patients. Knowledge of the morphological and clinical features that characterize each form of MT might be beneficial for patients and guide clinicians for intervention when needed. Larger cohorts are needed to reproduce and clarify our findings.