My cat (5 months old) had certain infection near his neck area and suddenly he became very ill and wasn't eating anything at all. He was losing weight and his ribs were becoming visible. I contacted a vet and he gave medicines. As of now he's eating normally and gaining weight but I'm worried that a spray (which contains ketoconazole, chlorhexidine gluconate) when applied on him, his fur and skin turns black.Also he has a black crusty thing on his nose This is happening everytime and I have no idea what it is. Is it normal or something serious is happening? I'm attaching a few photographs of the infection. Please help 🙏🏼enter image description here

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  • 1
    To me, under the chin just looks like dirt caught in the fur, possibly adhering to the sprayed medication. That's a hard place for cats to wash themselves; you might try combing or dabbing with a warm washcloth.
    – keshlam
    Aug 7, 2023 at 20:17
  • what did the vet say when you asked about the black areas?
    – jsotola
    Sep 3, 2023 at 17:10
  • The vet said that it is happening due to the antifungal spray when applied. Anyway he has recovered and we are really happy for him. Thanks for commenting!
    – Anamitra
    Sep 4, 2023 at 18:50

1 Answer 1


Please note that I am not a vet.

To me this looks normal for the circumstance. It seems that your cat has a severe fungal infection of the skin, so the fungus damaged the skin. The medication kills the fungus, but it cannot repair the skin. That has to heal on its own. So now it peels off the damaged layers (like human skin peels after a severe sunburn), which you see as flaky bits in the fur.

The black color is probably due to the medication. I don't know why that is. Maybe the components in the spray turn black when they get in contact with the fungus or simply with air.

The thing about fungi is that the visible part is always small compared to the entire body of the fungus. If the infection was worst on the neck of your cat, the fungus probably already spread to other parts of the skin. That may not have been visible before, but the spray makes it visible.

In general the healed skin beneath the flakes looks healthy and it doesn't seem to hurt the cat, so you should continue treating your cat with it like the vet prescribed it.

  • Thanks! But the thing which I've no idea about is the black crusty thing which is formed on his nose and it's spreading towards his eyes. Any idea what it is ? Also he was very active before but now he usually sleeps calmly. Today I saw him running and chasing flies in my house's garden.
    – Anamitra
    Aug 4, 2023 at 17:56

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