Heliophobia

Heliophobia has two meanings:
 * a specific phobia: dread or avoidance of sunlight
 * excessive sensitiveness to sunlight.

Causes
Heliophobia is a problem that afflicts hundreds of Americans, but one that suffers from a lack of true research. The Pacific Health Center suggested that many people have been staying away from the sun because of growing fears about skin cancer. This is not technically heliophobia, simply an unfounded and illogical solution.

Medical conditions such as keratoconus, which is an eye disorder that results in extreme optic sensitivity to sunlight and bright lights, and porphyria cutanea tarda, which causes the skin to be overly sensitive to sunlight to the point of causing blisters, can result in heliophobia.

Since heliophobia forces its victims indoors, heliophobia causes a Vitamin D deficiency problem. This can be corrected by taking Vitamin D supplements or drinking Vitamin D fortified milk.

Hypersensitivity
In chemistry or biology the terms heliophobic/heliophobe refers to an organism or substance that is sunlight-sensitive or has an aversion to sunlight.