Dermatology: Practical and Conceptual Image Letter | Dermatol Pract Concept. 2024;14(4):e2024253 1 Sulfasalazine-Induced Nail Changes: A Unique Clinical Observation Shrinivas Patil1, Anuj Bhatnagar1, Debdeep Mitra1 1 Department of Dermatology, Command Hospital Air Force Bengaluru, India Citation: Patil S, Bhatnagar A, Mitra D. Sulfasalazine-Induced Nail Changes: A Unique Clinical Observation. Dermatol Pract Concept. 2024;14(4):e2024253. DOI: https://doi.org/10.5826/dpc.1404a253 Accepted: June 14, 2024; Published: October 2024 Copyright: ©2024 Patil et al. This is an open-access article distributed under the terms of the Creative Commons Attribution- NonCommercial License (BY-NC-4.0), https://creativecommons.org/licenses/by-nc/4.0/, which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original authors and source are credited. Funding: None. Competing Interests: None. Authorship: All authors have contributed significantly to this publication. Corresponding Author: Shrinivas Patil, Department of Dermatology, Command Hospital Air Force Bengaluru, India. Phone: +91-8867659749. Email: shrinivas93doctor@gmail.com Case Presentation A 45-year-old male with a 7-year history of reactive arthri- tis visited our Dermatology Clinic, reporting yellow-brown fingernail discoloration that had gradually developed over weeks, most pronounced in the nails of the left index and ring fingers (Figure 1A). No other nail changes were noted. He had been on sulfasalazine (1 g twice daily) for two years before noticing discoloration. There were no concurrent medications or relevant medical history. Examination re- vealed a distinct yellow-brown hue mainly on the middle and ring fingernails. Dermoscopy (Figure 1B) showed a simi- lar hue without melanin pigments. Toenails were unaffected, with no onycholysis or hyperkeratosis. Lab tests revealed normal blood count, liver, and thyroid function. Chest x-ray was unremarkable. No fungal elements were detected in nail clippings. Sulfasalazine was stopped. Two months after dis- continuation, the nail discoloration abated. Teaching Point The sulfapyridine component in sulfasalazine is mainly responsible for hypersensitivity reactions, manifesting as cu- taneous rashes in <5% of patients, typically maculopapu- lar, pruritic, and generalized. Other adverse events linked to sulfasalazine include erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis, drug reaction with eosinophilia and systemic symptoms, lichenoid eruption, lupus-like syndrome, and phototoxicity. Sulfasalazine use is also associated with Raynaud phenomenon, hair thinning, and cutaneous pigmentation [1]. Sulfasalazine-induced nail discoloration, a rare adverse effect, mimics yellow nail syn- drome. Recognizing this association is crucial for accurate diagnosis and management. Prescribers should monitor nail discoloration as a potential adverse effect, ensuring timely rec- ognition and discontinuation of the drug. Further research is needed to understand sulfasalazine-induced nail changes [2]. 2 Image Letter | Dermatol Pract Concept. 2024;14(4):e2024253 References 1. Mushtaq S, Sarkar R. Sulfasalazine in dermatology: A lesser explored drug with broad therapeutic potential. Int J Womens Dermatol. 2020 Feb 13;6(3):191-198. DOI: 10.1016/j.ijwd .2020.01.009. PMID: 32637543; PMCID: PMC7330441. Figure 1. (A) Distinct yellow-brown hue involving the middle and ring fingernails. (B) Dermoscopy (DermLite 5, ×10, polarized) displaying a yellow-brown hue involving the distal nail plate, with no melanin pigments. 2. Tekeoğlu I, Sağ S, Kamanli A, Sağ MS, Erdem T. (2015). A Rarely Seen Side Effect of Sulfasalazine: Yellowish Colour in Toenails. Int J Med Pharm Case Reports. 2015:5(4), 1–4. DOI:10.9734 /IJMPCR/2015/21498.