Type IV hypersensitivity to Mycobacterium tuberculosis antigen may manifest as:

Phlyctenular Keratoconjunctivitis is believed to be a Type IV hypersensitivity reaction (delayed hypersensitivity) to tubercular or other bacterial proteins. Phlyctenular keratoconjunctivitis is a delayed hypersensitivity response, in most cases in developed countries to S aureus or other bacteria that proliferate on the lid margin in association with blepharitis. Peak incidence of this disease is between 3- 15 years of age. Incidence is higher in girls, and the disease is common in under nourished children living in unhygienic condition. A phlyctena is a pinkish white elevation commonly appearing at the limbus in the bulbar conjunctiva. Engorged conjunctival vessels cluster around at its base and the surrounding conjunctiva may be mildly hyperemic. Rx: Topical coicosteroid therapy shoens their duration and decreases scarring and vascularization. In the staphylococcal type, the acute staphylococcal infection and chronic blepharitis need to be treated. Ref: Biswell R. (2011). Chapter 6. Cornea. In P. Riordan-Eva, E.T. Cunningham, Jr. (Eds), Vaughan & Asbury's General Ophthalmology, 18e. ; Pediatrics : A Concise Text By S K Kabra, Pages 138, 284.