Scleritis (inflammation of sclera) is a strong indication of the underlying medical problem. It can be due to fungal, viral or parasitic infection, trauma, exposure to chemicals, poisonous gases or due to post-surgical complications.
Mast cells are granulated cells typically found in connective tissue. These cells mediate immune responses to foreign particles. In particular, they release large amounts of histamine and enzymes in response to antigen recognition.
Histamine is a chemical mediator, which takes part in allergic type of inflammatory reaction (hypersensitivity reaction). Histamine is stored inside the granules of Basophils and Mast cells and is released during inflammatory response. Fig 1 : Following is a diagram of a mast cell.