Hi there, cracks at the corners of the mouth is a distinct iron deficiency sign. I would ask to have your iron stores measured.
Sometimes zinc deficiency can also do that, or eczema. However it is a recognised iron deficiency sign so I would start with that. If you have any signs of anaemia such as tiredness, breathlessness on exertion or dizziness, I would see your doc soon. Anaemia also tends to make you feel very cold.
New stuff: GERD. Interstitial Cystitis
Lifelong stuff: Food allergies, eczema, asthma