Interesting you mention this as I recently wondered the same thing.  Our endo swore it had no relationship to one another.  This summer our daughter, 10 yr old swcah, had a major suntan from so much outdoor sports and swimming.  One day she just had an itching attack and there were the white spots.  The dr’s chalked it up to a cholrine allergy but she had never had one before and never any spots any where else on her body only the thighs.  Let me know what you find out.