At first this was attributed to just plain old embarrassment. After all, Pluto was demoted in 2006, being told that he was just a "dwarf planet." Pluto's still blushing about that one. But further investigation by scientists has revealed the real cause of the latest reddish appearance: a serious case of measles.
The planet Mars is an unsympathetic witness to the illness of Pluto and has stated, "He masqueraded for many years as a REAL planet, so he deserves what he gets. Let him eat cake." It's clear that Mars is insanely jealous of all the attention Pluto is getting. Mars has even gone so far as to remind all who will listen, "Remember, I am the one who has always been known as the Red Planet. No dwarf planet is going to take that title away from me."
Meanwhile -- in an amazing coincidence -- in the Disney Kingdom down here on earth, Disney dog Pluto has also come down with measles! And he's taking extra-good care of himself during his illness. "After all," he's said, "I'm no spring chicken." He doesn't like to reveal his exact age, but friends have confirmed that he's almost 80 years old!