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Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
Phlycten is due to-
assistant
The correct answer is  Phlyctenular keratoconjunctivitis is a characteristic nodular affection occurring as an allergic response of the conjunctival and corneal epithelium to some endogenous allergens to which they have become sensitized. Phlyctenular conjunctivitis is of worldwide distribution. However, its incidence is higher in developing countries. ref: A K KHURANA OPHTALMOLOGY,E4, Page-77