A dog's nose can become dry if he lies in the sun too long or is dehydrated. A dry nose can also be caused by sunburn or skin disorders.
If a dog has a dry nose, he needs a thorough examination. Some causes of dry nose are minor, while others are reasons for serious concern. If there is a nasal discharge of bubbly, thick, black, yellow or green liquid, contact a veterinarian immediately. If the dry nose is a result of dry skin due to sunburn, apply a lotion made to protect dogs' skin. Repeated sunburn can cause skin cancer in dogs.