Case series of 406 vernal keratoconjunctivitis patients: a demographic and epidemiological study

Purpose: To evaluate the specific allergic sensitization and epidemiological characteristics of vernal keratoconjunctivitis (VKC). Methods: This retrospective non-comparative case series included 406 VKC patients. Data included patient and family histories, and results of allergic tests. Annual incidence and prevalence rates were calculated for a cohort of 128 VKC patients from the greater Padua area. Results: The great majority of VKC patients were male (76%), with a male : female ratio of 3.3 : 1. A skin prick test, specific serum IgE or conjunctival challenge was positive in 43%, 56% and 58% of patients, respectively. In the cohort of patients from the Padua area, the prevalence of the disease was 7.8/100 000, with a higher rate in young males (57/100 000) compared with young females (22/100 000), and lower rates in people over 16 years of age (3.8/100 000 in males, 1/100 000 in females). The incidence of VKC was 1/100 000, with a higher rate in males under 16 years of age (10/100 000) compared with females (4.2/100 000). In people over 16 years of age, the incidence of the disease was 0.06/100 000, with no difference between males and females. Conclusions: An IgE-mediated sensitization was found in only half of the VKC patients. Vernal keratoconjunctivitis is not a rare event in the paediatric population but is an extremely rare new disease in adults.