There is a Fungi on my guinea...

Question
There is a Fungi on my guinea pigs nose and it is slowly getting werse,
How can I fix it?  

Answer
Hi there!  Many things can cause what your guinea pig is experiencing.  Mites, Scurvy, or an unclean cage/certain bedding materials can cause growths like these.
Mites:
These are microscopic parasites that feed off of their host, which can cause scabby, irritated skin and often times a skin infection.
Treatment: Your veterinarian will be able to prescribe your guinea pig a medication to kill the mites in spray form, and also an antibiotic to cure/prevent infection.
Scurvy:
Scurvy is a disease that is caused by a vitamin C deficiancy.  Guinea pigs, like humans, do not make their own vitamin C and need either a vitamin C supplement or a bit of fruits (oranges, apples,ect.) per day to keep their vitamin c level up.
Treatment: Begin with a vitamin C supplement, which can be obtained from your local pet store.  There are supplements that go into the food, and some that go into the water.  I tend to favor the supplements that are put into the water source.  Also, feed your guinea pig a sliver of peeled orange per day. If there is no improvement within 2 weeks time, or symptoms continue to be persistent or become worse, a veterinary visit will be needed for vitamin C injections and antibiotics.
Cage:
A guinea pig's cage should be cleaned daily.  There are plenty of bacteria that home themselves in the urine and feces in a guinea pig's cage.  Replacing the bedding daily and cleaning the cage thoroughly with bleach water weekly will eliminate the growth of bacteria.  Pine and cedar beddings can also cause skin irritations and respiratory problems.  If you use these types of beddings, it would be most beneficial to switch to a recycled newspaper bedding that offers the same absorbancy and odor control. My favorites are Yesterday's News and Care Fresh.
I hope this has been helpful. If you have any other questions, please feel free to ask!
Hilary