I wonder what the difference is between inflammation and irritation, especially in the context of tendinopathies.
I sometime see the two terms employed synonymously, e.g. in this Healthline article:
Tendons are thick cords that join your muscles to your bones. When these tendons become irritated or inflamed, it is called tendinitis. This condition causes acute pain and tenderness, making it difficult to move the affected joint.
or this Johns Hopkins University article:
Allergic conjunctivitis is inflammation or irritation of the clear mucous membrane lining the inner eyelids and sclera. This lining is called the conjunctiva.
In the context of tendinopathies, I would tend to believe they are synonymous as I cannot think of any other type of irritation other than inflammation, but I am not sure.