What Causes Swollen Lips With Cracks And Dryness In The Morning?

My lips are swollen every morning. Then throughout the day the swelling eventually goes down; however, they become very dry and cracked. Today, the swelling has occurred again, but parts of my lip are discolored (and black). I've tried an elimination diet and removed food that I might be allergic to, such as wheat (and gluten) and cow's milk. Are there other causes for this condition besides allergies? Or, could it be another food I'm allergic to?