There are broad amounts of ways OCD can manifest itself. OCD can create a fear of almost anything, even something as simple as colors. Yes, colors.
A common color people with OCD fear is red. Red can have an association with blood. If someone with OCD has fears and obsessions about blood, violence, death, etc. red can become something to avoid at all costs. And of course, avoidance is the compulsion. Another common color for obsessions is black. This is because it can have a similar association with death.
For me, the color my OCD latched onto is blue. Blue is associated with sadness, depression, negative thoughts. My OCD decided that if I wore blue then I would have another episode of depression. In response I avoided wearing blue for months. However, by working on my OCD with ERP (exposure and response prevention therapy) I have for the most part gotten rid of this fear. I can wear blue almost whenever I want to. Yay for OCD victories!
Something I want to clarify though is that when an OCD obsession focuses on a color, this is not the same thing as a phobia. I have a phobia of blood, but my OCD does not have any obsessions about the color red. They are separate in my case. To understand what fears are OCD it is all about the O’s and the C’s (obsessions and compulsions). For example, when I would go to wear a blue piece of clothing this is what the obsessions sounded like:
BLUE! Ahh Blue will make you think sad thoughts. You can’t think sad thoughts. Then you will feel sad. Then you will get depressed. Then you will be depressed forever. I can’t feel like that again. Ahh I can’t wear blue.
My anxiety would surge and the compulsion? I would put down the shirt, pick something else, and reinforce my fear of the color blue.
Phobias are different though. When I see blood I feel uncontrollable fear, rather than the almost logical anxiety of an OCD obsession. I have to look away or I may pass out. With this phobia I almost stop thinking completely, whereas with OCD you think too much. Makes sense?
I think the best way to understand OCD fears associated with colors is to think about your own associations with colors. Maybe yellow=sunshine, green=luck, and purple=royalty or relaxation. Everyone makes associations with colors. With OCD though we take them far too seriously because they come with a big bundle of anxiety and we want to find a way to avoid this anxiety (so we avoid the color). If you can imagine your own associations with color controlling you in this way, then you can imagine what it is like to have this version of OCD.
Have a sunny, yellow day.
Update: I love this blog post from another individual whose OCD created a fear of a color, in this case purple.