Retinal artery occlusion as a probable idiosyncratic reaction to topical minoxidil: a case report

Background Minoxidil hair formulation is commonly used for the treatment of male or female androgenic alopecia. This over-the-counter product is considered safe, but should be used with caution. Ocular side effects following topical minoxidil use are rarely reported. In this paper, we report a rare case of inferior hemiretinal artery occlusion possibly caused by topical 5% minoxidil treatment. Case description A 21-year-old Asian Indian male presented to the retina clinic with sudden onset blurring of vision and superior visual field loss in the right eye since morning. He was diagnosed with androgenic alopecia and was on treatment with topical 5% minoxidil spray twice a day for the last 3 years. On examination, his corrected distance visual acuity was 6/6, N6 in both eyes. Anterior segment examination and intraocular pressure in both eyes and left eye fundus were within normal limits. Right eye fundus examination showed features suggestive of inferior hemiretinal artery occlusion, which were confirmed on fluorescein angiography and optical coherence tomography. A detailed systemic evaluation and investigations (blood pressure, random blood sugar, hematological and coagulation profile, serum homocysteine level, Mantoux test, chest x-ray, cardiac two-dimensional echography, thyroid function test, and immunological profile) did not detect any abnormalities. The ocular condition and its visual prognosis were explained to the patient, and he was asked to review after 4 weeks. Conclusion Though there is no definite cause–outcome relationship between topical minoxidil use and retinal artery occlusion development, this possibility should be kept in mind when observing retinal vascular occlusion cases with concurrent use of topical minoxidil.