Photos of Michael Jackson’s oldest son show him with a large patch of discolored skin — a symptom of a condition his father claimed changed his skin color.

Prince Michael, 13, was spotted at a swimming pool while on vacation in Hawaii last week with his siblings Paris, 12 and Prince Michael II, 8. The white patches of skin, seen under his right arm, have sparked speculation that he suffers from vitiligo.

Vitiligo is an autoimmune condition, where the body attacks the melanocytes that give skin its color. It results in a loss of pigment, Dr. Doris Day, an attending dermatologist at Lenox Hill Hospital in New York City, told FoxNews.com

"The skin may appear white or even translucent which can make it look pinkish due to the underlying bloodvessels," she said.

Day added that the condition, which can occur at any age, isn’t necessarily hereditary. If a parent has an autoimmune disease, their children have a higher chance of also having an autoimmune disease, but not necessarily the same one.

“It is possible but rare to pass it down to a child,” said Dr. Ariel Ostad, clinical assistant professor in the Department of Dermatology at NYU Medical Center.

Vitiligo most commonly affects skin around any openings, including the mouth, the eyes and genitals, as well as around the extremities.

It isn’t clear whether Prince Michael has vitiligo, or that his father ever had it. But a topical treatment sometimes used for vitiligo, benoquin, can remove the remaining pigment from a person’s skin, which some believe is what Michael Jackson did.

“For people who have lost a large percentage of their pigment, they opt to go all light,” said Day, who added that topical steroids are used if the condition is caught early.

Another option is light therapy, Ostad said.

“Treatments involve topical cortisone creams, phototherapy (standing in a light box to absorb the light) and Lasers,” he said.

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