I would like to know if my sister really has OCD. She claims that I'm dirty, and never comes near me. This has severely hampered our relationship. Thus, it seems like her disorder revolves mainly around me, and from what I know about OCD, that's strange.

Sorry to hear that your sisters difficulties are affecting your relationship. While I can't say whether or not it is OCD without knowing more about her, what you explain is actually a common problem for those suffering from contamination OCD. That is, not being able to touch a contaminated family member. I know it would be hurtful, but you must remember not to take it personally as it is just the OCD. If she has contamination OCD, then likely many of the things around her feel "dirty" and cause her distress. So it could be you touched something she thought was dirty, or went to a place that she feels is contaminated and brought the contamination home on your person. Or she may even just feel that something about you just does not feel "right" so she needs to avoid you. She may be doing this for what she perceives as the safest thing or even for your own safety as well. If you had a good relationship before this and she does have OCD, then you need to recognize that it is her illness and not negative feelings towards you.

Real, clinical OCD is a very debilitating disorder that can greatly affect relationships. Unfortunately the people closest to the OCD sufferer are usually those who face the greatest brunt of the disorder. Those with OCD often get their family members to assist with rituals and compulsions. Hopefully at some point your sister will seek treatment if this is indeed OCD (if she is not already doing so), but in the mean time you can at least know that it is a common problem and that is the disease and not her. Only she can choose to get treatment, but that should not stop you from encouraging her to do so as well.

Best of luck,
Dr. Williams