My DS has had a runny nose every day since he was around 16 weeks old. He is now 15 months. It is sometimes worse than others, but I am wondering if he may be allergic to his milk. He was breastfed for 4 weeks but since then has been having Aptamil 1st (I had severe PND and was gutted I had to stop feeding him). Since he was 1 his bottles have been half formula and half cow's milk. Any advice welcome please.