2020 updates by Cathy Bickel, KJ Fuller
Some gerbils develop a red and irritated nose.
Sometimes the fur around the nose is also lost. The nose can get crusty, and may bother the gerbil so that she wipes or scratches at it, making it worse. Light-colored or red-eyed gerbils, like blue-eyed blond people, often have the most sensitive skin.
Gerbils who have a red nose, have a runny nose. There are a few major reasons for having a runny nose. Allergies and Illness. Often the first signs of an Upper Respiratory Infection is having a red nose. They may also have red stains around their eyes, which is more more obvious on lighter colors. If this is the first time your gerbil has had a red nose, more than likely they have a cold or sinus infection.
Chronic red nose can be caused by a bedding allergy. Carefresh is the worst offender due to high dust levels and the bedding's tendency to hold moisture, but gerbils can be allergic to any type of bedding or nesting materials, even to toilet paper. Allergies may develop over time, so even if you've been using a bedding for a long time, a red nose means you need to try a new brand. Dusty beddings are the worst offenders.
To treat the chapped nose itself, put a tiny dab of plain vaseline on the end of a Q-tip and wipe the ointment on the gerbil's nose, trying not to block the nostrils. Do not use Neosporin, as the gerbil will immediately try to wipe it off and will end up licking it off her paws and eating it. Neosporin is not safe for consumption. If the gerbil does not improve, you will need to take it to a vet for oral antibiotics.
Change the bedding immediately, and use disinfecting wipes on the cage and accessories. Corncob bedding and shredded printer paper or crinkled craft paper like Eco-bedding are good non-allergic alternatives. It may take a couple of weeks to clear up a badly irritated nose.