Department of Rheumatology, 424 General Army Hospital, Thessaloniki, Greece.
Correspondence to: G. Sakellariou, Department of Rheumatology, 424 General Army Hospital, 3 Labraki Str., 54638, Thessaloniki, Greece. E-mail: sakelgr{at}otenet.gr, sakellariou.doc{at}mycosmos.gr
I thank the authors for their valuable comments on the paper that reported a case of Behçet's disease with scleromalacia perforans, which is a necrotizing scleritis without inflammation [1]. The patient was referred to department for the first time and presented a scleromalacia perforans lesion with iridocyclitis in the right eye on ophthalmological examination. After performing extensive laboratory tests and an endoscopic examination with biopsy, treatment with prednisolone at a high dose of 75 mg/day plus azathioprine 150 mg/day was started due to the severe ocular presentation. In 2000 episcleritis of the right eye was diagnosed in the patient by an ophthalmologist. The same physician reported progression of episcleritis to scleromalacia perforans 1 yr later.
Episcleritis was defined as oedema and injection confined to the episcleral tissue, and scleritis as oedema in the episcleral and scleral tissue with injection in both the superficial and deep episcleral vessels. Watson and Hayreh [2] proposed a classification of episcleritis and scleritis, and reported no progression of episcleritis to scleritis, except in the case of herpes zoster. The distinction between episcleritis and scleritis is important because episcleritis, in contrast to scleritis, is usually a benign, self-limited disease that is rarely associated with ocular complications and systemic disease [35].
Cohort studies have shown that occasional cases of episcleritis may progress to scleritis. In a study of 100 patients with episcleritis, there was progression of episcleritis, which was not associated with infectious disease, to scleritis in 3 of 28 patients who experienced recurrences [4]. Of 37 patients with episcleritis in another study [5], one patient with episcleritis associated with rheumatoid arthritis subsequently evolved into scleritis during the follow-up. Also, patients with scleritis who experienced a recurrence of their disease can progress to another subtype throughout the course of follow-up [6].
Episcleritis is the most difficult differential challenge in patients who have scleritis. Although the superficial layers of the anterior segment are visible by slit lamp, the subsurface structures are difficult to observe with this technique. Scleritis not evident by slit-lamp examination, even when using additional vasoconstrictor tests, could sometimes be detected by the ultrasound biomicroscopy technique [7].
In conclusion, progression of episcleritis to scleritis can occur, even though this is rare. However, scleromalacia perforans misdiagnosed as episcleritis at the initial presentation cannot be excluded in the patient of this case.
The author has declared no conflicts of interest.
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