What Causes Itchy Fluid Filled Blisters On Earlobe?

i have a cluster of 3 small, itchy, clear fluid filled blisters on one earlobe and i was wondering what it could be caused by. The skin underneath is a red and very slightly swollen. I do have an ear piercing but the blisters are not directly on the piercing. I seem to keep getting small red bumps on the same earlobe but never blisters before. What could be causing this?