As dry skin is lacking enough oil in the skin its protective barrier is impaired.
Dehydration can occur with this skin type as there is not adequate oil to prevent its evaporation. Ensure you hydrate internally with fresh water and externally with water binding ingredients.
Dry skin may also be prone to sensitivity as the weak protective barrier cannot keep out irritants. Look for essential fatty acids and anti-inflammatories in moisturizers to re-build the protective barrier.