This interventional study aims to evaluate the efficacy of oral administration of Lactobacillus Rhamnosus GG in preventing relapses of ocular inflammation in Vernal Keratoconjunctivitis (VKC) patients.

Vernal keratoconjunctivitis (VKC) is a chronic allergic disease, characterised by ocular surface inflammation lasting all year with seasonal relapses. Active phases of VKC are characterised by intense ocular symptoms and require treatment with topical steroids to control inflammation and corneal damage. To date, safe and effective therapies in preventing relapses of VKC are not available. Recently, the use of oral administration of probiotics for allergic diseases have been proposed. No data are available on the effects of probiotics on ocular allergies. This multicenter, double-masked, randomised, controlled clinical trial will allow to obtain more data on the efficacy of oral treatment with Lactobacillus Rhamnosus GG in patients affected by VKC. Patients with VKC will be treated with Lactobacillus Rhamnosus GG or placebo in addition to ketotifen fumarate 0.025% eye drops (standard treatment). The number of relapses per year, signs and symptoms of the disease, total symptom score (TSyS), total sign score (TSS), biochemical and molecular parameters will be evaluated at different time points.

Inclusion Criteria:

• Diagnosis of VKC performed on the basis of personal and family history of systemic allergic diseases, clinical examination (presence of conjunctival tarsal and/or limbal papillae) and presence of eosinophils in the conjunctival scraping.

Exclusion Criteria:

• Contact lens wearers,
• Patients affected by other ocular diseases,
• Patients subjected to ocular surgery in the preceding 6 months,
• Patients under eye drop or systemic treatments for other diseases,
• Patients enrolled in experimental trials in the preceding 6 months.