Habronemic blepharoconjunctivitis in horses.

This study investigates Habronemic blepharoconjunctivitis in horses, detailing its clinical characteristics, histological findings and treatment methods, while underscoring the risk of misdiagnosis if only one section is evaluated.

Clinical Characteristics of Habronemic Blepharoconjunctivitis

• Habronemic blepharoconjunctivitis, a disease in horses, tends to present clinically as raised yellow, gritty plaques on the palpebral (eyelid) and bulbar (white of the eye) conjunctivae, which are the mucus membranes that cover the front of the eye and the inside of the eyelids.
• Lid granulomas (inflammatory growths) and blepharitis (eyelid inflammation) were also observed in some instances of this disease.

Diagnosis and Histologic Examination

• The presence of mast cells, eosinophils (a type of white blood cell), and collagenolysis (the breakdown of collagen) were commonly seen in most histologic examinations of the eye sections.
• However, if only one section of the eye is examined, there could be a possible misdiagnosis of mastocytosis (a disease characterized by an excessive number of mast cells), highlighting the importance of comprehensive evaluation for accurate diagnosis.

Treatment and Management

• Treatment generally involved the use of larvicidal mixtures for lid lesions and organophosphate ophthalmic drops paired with corticosteroids for the inflammation of the conjunctiva, or conjunctivitis.
• However, if the cornea (the clear, front layer of the eye) was damaged by these gritty conjunctival plaques, the healing process could be prolonged because the usage of corticosteroids, which could potentially slow down healing, would be contraindicated.