Vitiligo or white spot disease or leukoderma
White spots, or patches on your skin are usually caused by either vitiligo or tinea versicolor. Sometimes Eczema can also cause white patches.
Vitiligo kills cells that produce the pigments for your skin. Although not yet fully understood why, it is an autoimmune disease; as your body mistakenly sees the pigment cells as harmful and your immune system attacks them. The white patches feel and look like your normal skin, just with less color.
Mostly affected aare the face, feet, knees, hands and elbows. If your skin is darker it is of course more noticable
Tinea Versicolor, the chronic fungal infection most common in adults and young adult males is more likly to be found in hot climates. The skin area affected by tinea versicolor will not darken whilst tanning and can stay lighter then the rest of your skin.
A dermatologist will diagnose the skin condition for you.