I have psoriatic arthritis which can cause thickening of the toenails however my other toenails are mostly ok. Some of my toes are swollen but this one isn’t as bad as the others. I do have this black mark on the nail though which i know is probably related to the arthritis but also black spots = argh and panic a bit! I don’t want to be bothering the GP about nothing when half the country is stricken with flu and other viruses- but do I need to? This isn’t dodgy is it?