The unknown silent drug reaction in acne patients: rare case of isotretinoin-induced haematuria

Abstract

Background: Acne vulgaris is one of the most frequent visits to primary care physicians and dermatologists alike. Isotretinoin is the backbone of acne treatment. In most countries, depending on the health care system, isotretinoin is prescribed by dermatologists but primary care physicians are a part of the follow-up and interpreting analysis. Adverse effects of isotretinoin on the kidney and urinary system are mostly limited to sparse case reports. Specifically, gross and microscopic haematuria is not mentioned to be associated with isotretinoin. Lack of data regarding these adverse effects can lead to doubt regarding further patient management not only with dermatologists but also primary care physicians. Objective: We report a 16-year-old male patient with isotretinoin-induced haematuria with multiple episodes and subsequent challenge and de-challenge. No personal or familial history of nephrological disease was present. Ultrasound imaging and nephrology workup was within normal limits. Other aetiologies were excluded. Nephrology consult stated there was no contraindication for isotretinoin use and was reinstated at 0.6 m/kg/day. More frequent observation was indicated until completion of isotretinoin. Conclusion: Our case raises awareness to other dermatologists and primary care physicians that haematuria can be secondary to isotretinoin but not a contraindication for further use if asymptomatic and microscopic. More extensive evaluation and monitoring should be done if the patient is symptomatic with other abnormalities and symptoms. Urinalysis should be a part of routine follow-up monitoring in patients on isotretinoin. Furthermore, delineating and differentiating when to refer to a nephrologist is essential for physicians, patients, and the health care system overall. Lay summary Red blood cells in the urine (called haematuria), whether seen by the eye or seen only on urinalysis can be caused by many diseases and/or drugs. The most effective treatment of acne is isotretinoin and its side effects are for the most part known. Renal and/or urinary side effects are extremely rare. We report a 16-year-old male patient with isotretinoin-induced haematuria with multiple episodes and subsequent challenge and de-challenge. When isotretinoin was discontinued, no red blood cells were seen in the urine. When isotretinoin was reinstituted, red blood cells were seen once again in the urine. It is important for physicians to know of this rare side effect as it prevents unnecessary referrals to nephrologists, while on the other hand raises awareness of the connection and helps in understanding when isotretinoin should be potentially discontinued and patients referred. © The Author(s) 2023. Published by Oxford University Press. All rights reserved.