Sir,

We were interested to read Jain et al's1 finding of pseudodendritic keratitis associated with meibomitis in young healthy male subjects. Recently, two patients who demonstrated the typical morphological features described were treated at the West of England Eye Unit, Royal Devon & Exeter Hospital, UK. The first was a 6-year-old Caucasian male with a 2-day history of a red right eye associated with photophobia. He had complained of similar symptoms intermittently over the previous year. On examination, there was marked conjunctival infection, evidence of meibomian gland dysfunction, inferior marginal stromal infiltrates, widespread punctate epithelial erosions, and a horizontally orientated pseudodendrite in the inferior cornea. The second patient was an 8-year-old Caucasian female with a 4-month history of recurrent redness and irritation in the left eye, which had not responded to topical antibiotics. She had meibomian gland dysfunction, an inferotemporal marginal infiltrate, and a non-staining, horizontally orientated pseudodendrite inferiorly. Both patients responded rapidly to topical 0.5% prednisolone and oral erythromycin.2

In contrast to the series by Jain et al1, both had unilateral disease and one patient was female. Mechanical rubbing of the inflamed eyelids on the corneal surface was suggested as a contributing factor to the aetiology of these lesions and the use of a bandage contact lens was recommended as treatment. The fact that our patients responded rapidly to topical steroids indicates an inflammatory process underlying the pathogenesis. Enhanced cell-mediated immunity at the corneal limbus to staphylococcal cell wall antigens, expressed as delayed hypersensitivity (type IV), has been hypothesised as the aetiology of marginal keratitis. 3However, in rabbits subconjunctivally and topically immunized with staphylococcal antigens, corneal IgG antibodies have consistently been found4 and a precipitation line of antigen–antibody complex has been demonstrated in the stroma of rabbits injected with antigen and antibody from opposite sides of the cornea.5 Pseudodendritic keratitis in young patients with blepharitis may therefore represent an immune complex deposition or type III hypersensitivity reaction to staphylococcal antigen.