Black Fungus on a Cat's Nails

"I promise, there aren't any fungal problems here."
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When what appears to be a black fungus shows up on or around your kitty's nails, you might be concerned that she's suffering from something terrible. But remain calm, because whatever it is, medicine can help stifle the nastiness, which might not even be a fungus at all.

Fungal or Bacterial Infection

Those little paws of your kitty, cute as they might be, trample onto all sorts of nastiness. From the litter box to the toilet rim, fungi and bacteria tend to gather in large numbers on the bottom of your kitty's feet. Should she accidentally split her paw pad, break off a nail or otherwise damage her foot, all the nastiness has a chance to seep inside. The infection can affect both the paw pad and nail beds, leading to nail beds that take on a blackened appearance. The black color, which may not be fungus and instead discharge, may indicate a fungal infection, but a bacterial infection is also possible. With an infection, your kitty may refuse to put pressure on the affected paw, the pad or nail bed may appear reddened and swollen and it will usually smell something repulsive.


Pemphigus -- the name sounds nasty and the symptoms are even worse. Unlike an infection, pemphigus occurs when your feline's immune system goes bonkers and attacks her skin. Blistery, scaly, rough and blackish-reddish colored skin is what results. Your kitty's paws are a likely target, and the blackened color may surround her nails, although the nails themselves won't actually be affected. Note that the crusty skin won't appear completely black. It will usually consist of a mix of red, pink, gray and black and might even appear a bit purple. The skin disorder can also appear on other areas of your cat's body, especially her face and belly.

Outdoor Cats

Felines who are allowed to have some fun in the sun find themselves a bit dingy at times, with all the dirt available to them outside. What appears to be black fungus might actually be mud, soil, dried-on liquid or something else that poses no threat. Or, who knows, it might actually be bits and pieces of a forest-growing mushroom that your kitty picked at. Regardless, sometimes outside grime can be tough for your feline to scratch off, especially if it's caked on the top of the nail.

Vet Appointment

Here's the rule of thumb for taking your meowing friend to the vet for a funky black fungus-like nastiness on or near her nails: If something seems out of the ordinary, make an appointment. Her paws, nail beds and nails should never appear reddened or swollen or be plagued with blisters and scales. Her paws shouldn't smell bad, her appetite should remain normal and she should be as active as usual. If you notice any changes in her behavior, it's time to visit the doc.

Always check with your veterinarian before changing your pet’s diet, medication, or physical activity routines. This information is not a substitute for a vet’s opinion.

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