Vernal keratoconjunctivitis: an update

Vernal keratoconjunctivitis (VKC) is a bilateral, usually
seasonally recurrent, allergic inflammation of the conjunctiva,
characterised by limbal gelatinous hypertrophy and/or upper tarsal
giant conjunctival papillae. Although rare in temperate regions, it
represents an important cause of hospital referral in many parts of
Africa and Asia. Clinical and immunohistochemical studies suggest
that IgE-dependent (type I allergic) and IgE-independent (type IV
allergic) mechanisms are involved in the immunopathogenesis of VKC,
in which various inflammatory cells, including different T cell
subpopulations play an active role via a cascade of chemical
mediators. Endocrine, genetic, neurogenic, environmental and
socioeconomic risk factors have been identified. However, its
aetiology and pathophysiology remain unclear. The clinical course
of this disease is usually benign and self-limiting, but a minority
of patients will face very debilitating and sight threatening
complications. Topical corticosteroids are often used during
flare-ups in combination with mast cell stabilizers as maintenance
treatment for VKC. However this management is unsatisfactory in
controlling severe cases and avoiding recurrences. Non-steroidal
immune modulators such as ciclosporin A and tacrolimus are
promising alternatives, but tolerance to these agents needs to be
improved and production costs reduced. The purpose of this review
is to give an update on its epidemiology, immunopathogenesis and
management.