Case Presentation
A 45-year-old male with a 7-year history of reactive arthritis 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 revealed a distinct yellow-brown hue mainly on the middle and ring fingernails. Dermoscopy (Figure 1B) showed a similar 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 discontinuation, the nail discoloration abated.
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.
Teaching Point
The sulfapyridine component in sulfasalazine is mainly responsible for hypersensitivity reactions, manifesting as cutaneous rashes in <5% of patients, typically maculopapular, 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 syndrome. Recognizing this association is crucial for accurate diagnosis and management. Prescribers should monitor nail discoloration as a potential adverse effect, ensuring timely recognition and discontinuation of the drug. Further research is needed to understand sulfasalazine-induced nail changes [2].
Footnotes
Funding: None.
Competing Interests: None.
Authorship: All authors have contributed significantly to this publication.
References
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