Can antibiotics cause my dog's dull coat?

My dog has been on antibiotics for several weeks due to an infected cyst on his foot. It was surgically removed early-November and we just finished his antibiotics. A few weeks ago I started adding a skin and coat oil supplement to his food but there has been no change. His coat is very dull and dry. I also use the furminator once every week or so. Does anyone know if antibiotics can cause a dull coat?