Could tretinoin have caused eyebrow hair loss? (photos)

It is unlikely the retin-a is causing your eyebrows to thin.  You might want to see your board certified dermatologist for an in-person evaluation.  Some patients do develop alopecia areata in the eyebrows as well as the scalp and beard areas, so ask about that, although I don't see any evidence of that in the photos.  Alopecia areata is also not related to retin-a use.  If you are worried that the retin-a is causing the thinning, you could always take a break from it, or put some moisturizer on your eyebrows before putting the retin-a on the rest of the face to protect them.  Many of my patients use Latisse for their eyelashes, and apply any extra on the little brush to the eyebrows.  That might be an option for you also.  Seek expert care, and best of luck!

Thank you for your question and photographs. It's difficult to evaluate your skin through this type of forum because an in-person evaluation needs to be done. Tretinoin is not known to cause hair loss, but if you are concerned about using tretinoin, then hold treatment for a few weeks or until you see a physician. I highly recommend you consult with a board certified dermatologist to have your skin evaluated and to discuss treatment options that best suits your needs. Take care and good luck.