He's a male gray tiger/Russian Blue rescue cat, 9 years old (with me 7 years), excellent health, indoors only. He showed no change in appetite, water usage, litter box habits (or the contents of it!) or attitude. Coat, eyes, and temperature were fine. It was just this sudden change of his nose leather from dark brick to pale pink. A friend who has five cats said today that two of hers also get pale noses occasionally, and like me, she hasn't noticed any accompanying signs or symptoms. Does this indicate that the cat(s) should be checked? Or, if this "just happens sometimes," does anyone know why?