How are episcleritis and scleritis differentiated?
The significant pain associated with scleritis is the primary distinguishing feature. A blue/purple hue, rather than bright red discoloration, may be seen with scleritis. The presence of avascular areas within the regions of vascular engorgement is highly suggestive of scleromalacia perforans. In contrast, episcleritis is characterized by superficial inflammation of the loose vascular connective tissue overlying the sclera; it is typically brighter red in color, tender rather than overtly painful, and application of phenylephrine results in rapid resolution of erythema. Episcleritis and scleritis can coexist, which must be remembered when interpreting these results. Urgent evaluation by an ophthalmologist is necessary for an accurate diagnosis.
