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.
Diabetic dermopathy, also known as shin spots or pigmented pretibial patches, is a skin condition usually found on the lower legs of people with diabetes. It is thought to result from changes in the small blood vessels that supply the skin and from minor leakage of blood products from these vessels into the skin.ichen simplex chronicus (LSC), also known as neurodermatitis circumscripta, is an itchy skin condition causing thickened skin at the areas of skin injured by repeated scratching and rubbing. Lichen simplex chronicus is not a primary disease but rather the skin's response to chronic physical injury (trauma).