What causes dark spots?

Have you ever wondered what causes dark spots?

I have found this article which gives more detailed information on what causes dark spots on your skin:

Dark spots on the skin, also called hyperpigmentation, are a common skin problem especially beginning in middle age. There are a variety of conditions and agents that can cause dark spots to develop.

Skin Diseases that Cause Dark Spots
One of the most under-recognized causes of dark spots is post-inflammatory hyperpigmentation. This is a dark spot that occurs after some type of trauma to the skin - especially infections like acne. This and other skin diseases are listed here:

• Melasma
• Riehl's melanosis
• Poikiloderma of Civatte
• Erythromelanosis follicularis
• Linea Fusca
• Post inflammatory hyperpigmentation

Medications that Cause Dark Spots
Certain medications sensitize the skin to the sun and other medications can cause dark spots without sun exposure. The most common offending medications are listed here:

• Estrogens
• Tetracyclines
• Amiodarone
• Phenytoin
• Phenothiazines
• Sulfonamides

UV Light Causes Specific Types of Dark Spots
UV light is a major cause of not only dark spots, but also other types of skin damage. The various types of dark spots caused by UV light are listed here:

• Melasma
• Solar lentigines - freckles
• Ephelides

Other Causes of Dark Spots
These are other conditions or diseases that can cause dark spots:

• Pregnancy
• Liver disease
• Addison's disease
• Hemachromatosis
• Pituitary tumors

References:

• Rendon, Marta and Gaviria, Jorge. "Skin Lightening Agents." Ed. Zoe Draelos. Philadelphia: Elsevier, 2005. 103-4.

The article has been copied from About.com, link: Dark Spots on the Skin - What Causes Dark Spots