Maarij Mirza
Introduction
Vernal keratoconjunctivitis (VKC) is a type of bilateral allergic conjunctivitis that involves chronic inflammation of the conjunctiva that can also involve cornea. Typical onset is during childhood and it can present with seasonal variation with patient’s commonly experiencing flares during the spring and summer (1).
Epidemiology
The prevalence of VKC varies by region, with a higher disease burden in countries with humid and tropical climates (1). In Western Europe and the United States, VKC accounts for less than 1% of ocular diseases. In contrast, countries from the Middle East and Africa report prevalence ranges from 3-10% (2).
Despite VKC commonly affecting children, many cases persist into adulthood and epidemiological studies found that 10% of patient’s began experiencing symptoms as adults. Therefore, VKC can be classified as ‘early-onset’ as well as ‘late-onset’. Early-onset VKC was significantly more prevalent amongst males, whereas late-onset VKC showed similar rates of gender distribution (3).
Aetiology
The pathophysiology behind VKC has been thought to be a type 1 hypersensitivity reaction to airborne allergens involving the production of immunoglobulin E (IgE) antibodies by immune cells to result in acute inflammation. Studies have found that type 4 hypersensitivity reaction that is T-cell mediated may also play a role in inducing a late-phase allergic reaction. However, not all patient’s with VKC have shown to exhibit allergic sensitisation by production of IgE antibodies (4). Androgen levels can suppress immune activity and have also been proposed to lead to symptom alleviation during puberty in patients with VKC (5).
Clinical presentation
The main symptoms patient’s with VKC can experience are itching, ocular pain, foreign body sensation, blurred vision, mucoid discharge, photophobia and tearing.
From initial presentation patients may have an inflamed conjunctiva, palpebral thickening and pseudoptosis. They may also exhibit behaviours to alleviate symptoms such as frequent blinking or rubbing of the eyes (6).
Clinical findings include giant papillae (>1mm) that give a cobblestone appearance typically found on the upper tarsal conjunctiva. Horner-Trantas papillae around the limbus present as white dots filled with eosinophils and degenerated epithelial cells that are also typical.
Corneal involvement can also occur in VKC. Punctate epithelial erosions on the cornea result from mechanical trauma and toxicity from inflammatory cytokines which can be visualised with fluorescein dye. These can progress to form a shield ulcer which predisposes to other sight threatening complications. Superficial scarring within the cornea next to the limbus known as pseudogerontoxon and keratoconus can indicate chronic VKC (7).
Diagnosis
Diagnosis predominantly relies on clinical examination and comprehensive history taking. Skin prick tests, serum IgE levels and analysis of conjunctival scrapings for eosinophils are options available to support the diagnosis. Staining methods (fluorescein, lissamine green, confocal microscopy) can help evaluate degree of epithelial damage. Corneal topography is also recommended to screen for keratoconus (1). These are beneficial to use in conjunction with grading scales to determine the severity of VKC (8), (9).
Management
Most patients report spontaneous resolution of symptoms after puberty, however, some may still experience symptoms in adulthood (10). Topical lubricating drops or antihistamines can provide symptomatic relief in mild cases. In moderate cases or flare-ups, a short course of topical steroids and immunosuppressants can be used in addition. Prophylactic topical antibiotics may be required in cases of epithelial defects and surgical intervention may be required for shield ulcers that persist (11). In refractory cases of VKC, studies have shown the use of topical calcineurin inhibitors (tacrolimus ointment) may also benefit patients (12). Ultimately, avoidance of allergens and effective counselling around medical treatment regimens are key to managing the relapsing remitting nature of VKC in the long term.
References
1. Kaur K, Gurnani B. Vernal Keratoconjunctivitis. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024
2. Mehta JS, Chen WL, Cheng ACK, Cung LX, Dualan IJ, Kekunnaya R, et al. Diagnosis, Management, and Treatment of Vernal Keratoconjunctivitis in Asia: Recommendations From the Management of Vernal Keratoconjunctivitis in Asia Expert Working Group. Front Med (Lausanne). 2022 Aug 1;9:882240.
3. Di Zazzo A, Zhu AY, Nischal K, Fung SSM. Vernal keratoconjunctivitis in adults: a narrative review of prevalence, pathogenesis, and management. Front Ophthalmol [Internet]. 2024 Feb 15
4. Sacchetti M, Plateroti R, Bruscolini A, Giustolisi R, Marenco M. Understanding Vernal Keratoconjunctivitis: Beyond Allergic Mechanisms. Life (Basel). 2021 Sep 26;11(10):1012.
5. Di Zazzo A, Micera A, De Piano M, Coassin M, Sharma S, Bonini S, et al. Adult Vernal Keratoconjunctivitis: Clinical and biochemical profile of a rare disease. The Ocular Surface. 2019 Oct 1;17(4):737–42.
6. Dahlmann-Noor A, Bonini S, Bremond-Gignac D, Heegaard S, Leonardi A, Montero J, et al. Novel Insights in the Management of Vernal Keratoconjunctivitis (VKC): European Expert Consensus Using a Modified Nominal Group Technique. Ophthalmol Ther. 2023 Apr 1;12(2):1207–22.
7. Feizi S, Javadi MA, Alemzadeh-Ansari M, Arabi A, Shahraki T, Kheirkhah A. Management of corneal complications in vernal keratoconjunctivitis: A review. The Ocular Surface. 2021 Jan 1;19:282–9.
8. Leonardi A, Lazzarini D, Valerio ALG, Scalora T, Fregona I. Corneal staining patterns in vernal keratoconjunctivitis: the new VKC-CLEK scoring scale. British Journal of Ophthalmology. 2018 Oct 1;102(10):1448–53.
9. Bonini S, Sacchetti M, Mantelli F, Lambiase A. Clinical grading of vernal keratoconjunctivitis. Curr Opin Allergy Clin Immunol. 2007 Oct;7(5):436–41.
10. Doan S, Papadopoulos NG, Lee JK, Leonardi S, Manti S, Lau S, et al. Vernal keratoconjunctivitis: Current immunological and clinical evidence and the potential role of omalizumab. World Allergy Organization Journal. 2023 Jun 1;16(6):100788.
11. Ghauri AJ, Biswas S, Manzouri B, Barua A, Sharma V, Hoole J, et al. Management of Vernal Keratoconjunctivitis in Children in the United Kingdom: A Review of the Literature and Current Best Practice Across Six Large United Kingdom Centers. Journal of Pediatric Ophthalmology & Strabismus. 2023 Jan;60(1):6–17.
12. Fiorentini SF, Khurram D. Therapeutic effects of topical 0.03% Tacrolimus ointment in children with refractory vernal keratoconjunctivitis in Middle East. Saudi Journal of Ophthalmology. 2019 Apr 1;33(2):117–20.