my son takes vyvanse, has for atleast 2 yrs. we just increased the dose from 40mg to 50mg 1 1/2 mo ago. he is 14yrs old and 120lbs. he recently has had itchy/painful palms and feet and the other night his lips became swollen after sucking on an ice cube, his hands became painful and itchy after being outside in the cold with no gloves for a very short period of time. i have looked up cold urticaria and wondering if there is any relation to the vyvanse he is taking. saw something about withdrawl... he had missed a dose during this time frame, but just one day. is it likely this is the cause of his symptoms? should i be concerned?