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.
EPIDEMIOLOGYVernal keratoconjunctivitis (VKC) is a bilateral, chronic, external ocular inflammatory disorder, mainly affecting patients in their first or second decade.1-3 Although it is a rare allergic disorder in temperate regions, in many parts of Africa, Latin America and Asia VKC represents an important cause for hospital attendance, ranging from 3% to 6% of patients of all ages, rising to 33% and 90% in children and adolescents.2 4-7 A population prevalence of 4% to 5% has been found among African children.3 8 In large European and Asian case series boys appear to be affected more than girls, but this sex distribution is not found uniformly in Africa, and becomes less obvious with age.