I have several things wrong with me. One is a fairly early onset of rheumatoid arthritis, which is essentially one's own immune system attacking one's joint tissue, identifying the tissue as an invasive force. Another is idiopathic pulmonary fibrosis, which is significant scarring of my lungs (in particular the left), which makes it hard to breathe at the best of times and leaves my heart working twice as hard.
These aren't really visible, per se. They're not what one would call visible illnesses. I do HAVE some visible conditions, mind - side effects of the other two.
This is the reason I don't wear shorts.
Those are my legs, clad in the compression bandages that I have on 7 days a week.
The reason they are in compression? Well, there's two reasons; Lefty and Sheldon.