Reverse tan on ankles and feet??

I have noticed light brown freckle looking spots on my boyfriends leg/ankle region. They begin just below his calves and continue down around his ankles skip the tops of his feet and then start up again at the base of his toes and around the bottoms of his feet just above where the soles of his feet start.  It litterally looks like the reverse of a tan you get when you are wearing shorts and shoes with socks.  His legs are white and where his socks would be with the exception of the tops of his feet are dark.  I have looked at some on line pictures of age spots, but the pictures of the age spots appear to be much darker than his spots.

He is 49 years old and is on medicine to control his blood pressure.  I am hoping they are not in some how related to his heart, blood pressure, etc.

Thanks for your time!

[Dr_Aparna]

Hi,
This could be a fungal infection called Tinea versicolor or pityriasis versicolor, which  is a common skin infection caused by a yeast infection. This yeast is normally found on the human skin and only becomes troublesome under certain circumstances, such as a warm and humid environment.

It presents as pale, dark tan, or pink in color, with a reddish undertone that can darken when the patient is overheated, generally oval or irregularly-shaped spots of 1/4 to 1 inch in diameter, often merging together to form a larger patch.

Treatment is  topical antifungal medications - containing either 2.5% selenium sulfide (Selsun shampoo in UK, but not Selsun Blue which contains only 1%) or 2% ketoconazole (Nizoral ointment and shampoo) applied to dry skin and washed off after 10 minutes, repeated daily for 2 weeks.

Recurrence is common and may be reduced by intermittent application of topical agents (such as tea tree oil) or adding a small amount of anti-dandruff shampoo to water used for bathing.
ref:http://en.wikipedia.org/wiki/Tinea_versicolor