A value of NULL indicates that the value is unknown. A value of NULL is different from an empty or zero value. No two null values are equal. Comparisons between two null values, or between a NULL and any other value, return unknown because the value of each NULL is unknown.
Skin Spots on the Face. Most causes of spots on face are harmless. They can be a variety of colors including white, red, black or brown. Common causes include cumulative sun exposure, acne, and skin tags. Keratoacanthoma (hyperkeratosis) is a lesion that grows rapidly, usually on areas exposed to the sun.
Disseminated superficial actinic porokeratosis (DSAP) is a rare, non-cancerous, non-contagious skin disorder. Disseminated means that it is widely spread, most likely over the front and lower arms and legs -- areas that are typically frequently exposed to sun over a period of time.Superficial means that DSAP occurs on the outer layer of the skin.orokeratosis means that these skin changes are seen as a variety of flat, thickened lesions with slightly raised rims. You can feel this flaky rim when running your hand lightly down the arms and legs. DSAP is a chronic disorder; it can be treated, but it cannot be cured.