D1.199 - Severe vernal keratoconjunctivitis with allergic rhinitis treated with house dust mite (HDM) sublingual immunotherapy (SLIT)

Background: Vernal keratoconjunctivitis (VKC) is a rare, severe ocular allergic disease associated with major quality-of-life impairment. It often occurs in atopic patients and may be associated with allergic rhinitis, asthma or eczema. If inadequately controlled, VKC may lead to corneal and conjunctival complications with potential visual impairment. Pharmacological treatments are not always sufficient, and allergen immunotherapy may represent a disease-modifying option; however, evidence in VKC remains limited

Methods: A 15-year-old girl followed for ocular and nasal allergic symptoms since 2015, with recurrent exacerbations during the monsoon season and winter, presented with severe VKC characterised by bilateral ocular itching, redness and discharge, papillary reaction and limbal inflammation (limbal infiltrates/Trantas dots), associated with moderate–severe persistent allergic rhinitis (AR) without asthma, markedly affecting school and social activities. Symptoms systematically relapsed when topical ocular anti-inflammatory therapy (topical corticosteroids, NSAID eye drops and cyclosporine) was tapered despite oral antihistamines and intranasal corticosteroids. Skin prick testing was positive for HDM (Dermatophagoides pteronyssinus 9 mm; Dermatophagoides farinae 7.6 mm) and Blomia (8 mm), while other aeroallergens were negative. A standardized HDM SLIT tablet (12 SQ HDM; once daily) was initiated on 02 Aug 2025

Results:  Within 2 weeks of SLIT initiation, ocular and nasal symptoms improved. By 6 weeks, symptoms were clinically controlled with marked improvement in school and daily functioning, allowing discontinuation of intranasal corticosteroids within 1 month. All concomitant ocular and oral symptomatic treatments were discontinued by 6 weeks. At follow-up on 21 Dec 2025 (4.5 months after initiation), the patient remained symptom-free on ongoing SLIT alone (13 weeks without concomitant symptomatic medication); no relapse or SLIT-related adverse events were reported

Conclusions:  In this HDM-sensitised patient, initiation of a standardized HDM SLIT tablet (12 SQ HDM) was associated with rapid and sustained symptom control of VKC and AR, with a marked reduction in concomitant topical and systemic treatment burden