To the Editor:

An 84-year-old woman diagnosed in 2002 with limited cutaneous systemic sclerosis (SSc) that is characterized by sclerodactyly, telangiectasia, Raynaud phenomenon, gastroesophageal reflux, and antinuclear antibodies, but negative for ScL70 and anticentromere antibody, presented with left eye redness and pain. Her gastroesophageal reflux was treated with pantoprazole, and her comorbid inflammatory osteoarthritis was treated with hydroxychloroquine. She was diagnosed with scleritis of the left eye. She was evaluated for causes of scleritis. Antineutrophil cytoplasmic antibodies, angiotensin-converting enzyme level, rheumatoid factor, tuberculous QuantiFERON, and syphilis screen were negative. There was no clinical evidence of sarcoidosis or Sjögren syndrome. She was treated with oral prednisone 50 mg daily that was subsequently tapered. She underwent cataract surgery for her right eye, but her left eye cataract surgery was postponed due to scleritis activity. Prednisone was increased and azathioprine (AZA) 100 mg daily was added as a steroid-sparing agent. Her scleritis settled down with a dose of prednisone 20 mg daily. Cataract surgery was carried out, with a perioperative pulse of oral prednisone at 50 mg and then slow taper. Her scleritis recurred and persisted with slow oral prednisone taper over 5 months, prompting the initiation of an infliximab (IFX) biosimilar and discontinuation of AZA. IFX was chosen as she was unable to self-administer injections and preferred treatment in an infusion clinic where she could be assessed by the rheumatology team. She had resolution of eye pain, resolution of scleral injection, improved vision, and successful prednisone tapering within 3 months.

SSc is a rare systemic autoimmune rheumatic disease with the potential to affect virtually all organs. In a cross-sectional study of people with SSc, the most common ocular manifestations were eyelid tightness (51.1%), blepharitis (40%), keratoconjunctivitis sicca (48.9%), shallow fornices (15.6%), and retinal microvascular abnormalities (13.3%).1 Although cataracts frequently occur (42.2%) in patients with SSc, this is thought to be related to age and corticosteroids.1 We are reporting this case of SSc and scleritis due to its rarity, and to provide insights for treatment decisions, particularly as our patient not only responded to IFX but also because IFX facilitated taper of corticosteroids.

Scleritis refers to a painful inflammation affecting the sclera. It is categorized into anterior and posterior types, with the former being more prevalent. Anterior scleritis is then subdivided into diffuse, nodular, and sclerosing forms.2 Approximately 50% of scleritis cases are associated with underlying systemic conditions.2 The prevalence of scleritis in SSc is uncertain and limited to case reports.1

The approach to managing scleritis varies based on its severity. Typically, nonsteroidal antiinflammatory drugs are recommended as first-line treatment, followed by systemic corticosteroids (CS) if necessary. If a patient exhibits difficulty in tapering off CS or shows an inadequate response, the addition of an immunomodulating agent may be warranted. A study investigated the effectiveness and safety of antimetabolites in treating noninfectious ocular inflammation, including scleritis.3 Mycophenolate achieved faster control of ocular inflammation compared to methotrexate. AZA exhibited a higher incidence of treatment-related side effects when compared to the other 2 agents. In our case, AZA was discontinued due to its lack of efficacy rather than its adverse effects. It may be that our dosing at 2 mg/kg was insufficient, and that 3 mg/kg would have had a better therapeutic effect. There are insufficient data in the existing literature to make comparisons regarding the effectiveness and safety of various biologics for treating scleritis. Due to the rarity of scleritis in patients with SSc, much of the available data originates from studies on idiopathic scleritis or scleritis secondary to rheumatoid arthritis and vasculitis. A randomized trial examined the effect of rituximab on 12 patients with noninfectious scleritis that was refractory to systemic CS and at least one other immunosuppressive agent.4 The study found that 9 out of 12 patients achieved the primary outcome without significant adverse effects, though 7 of them required reinfusion. When comparing cyclophosphamide to other immunosuppressants such as AZA, cyclosporine, methotrexate, and mycophenolate mofetil, the efficacy of cyclophosphamide in treating necrotizing scleritis was similar to that of the other agents, although with a higher rate of discontinuation due to adverse effects.5

Monoclonal anti–tumor necrosis factor agents were found to be effective in controlling inflammation, reducing flare rates and sparing steroid usage.6 Ragam et al reported remission rates in patients treated with IFX and adalimumab of 77% and 67%, respectively, with no significant difference observed between treatments.7 Our case of difficult-to-treat scleritis has shown a beneficial effect of an IFX biosimilar, despite the patient experiencing initial ineffectiveness with multiple courses of CS and AZA. The long-term effectiveness is unknown. Our report indicates that scleritis can occur in SSc and offers a valuable insight in its treatment. Further cases resembling ours and extended posttreatment follow-up would provide additional helpful information.