Hello,
Whether the hives appered as an allergic reaction to the dissolving sutures or not depends on the material of the sutures and your body,s immune reaction to that material.Mostly dissolving
sutures are catgut(plain/chromium),vicryl,
monocryl or vicryl rapide(latest and least allergic).
Although your doctor is suspecting the stitches to be the source of allergy,but it is seen that many cases of hives are "idiopathic," meaning no cause is known.