Causes of blotchy skin can include melasma and hyperpigmentation, according to Everyday Health. These can be present as a result of changing hormones, especially in pregnant women.
Blotchy spots are more common in people who have a darker colored skin tone. This happens because there is more pigment already present in the darker skin and it is more prone to become excessive. Hyperpigmentation is a result of too much pigment being produced in the skin as a result of increased melanin production.
When the melanin producing glands of the skin are exposed to more sun or are affected by changing hormones, they will begin to produce more of the chemical that causes the skin to darken. They may not produce more melanin in all areas of the skin, causing the skin to look blotchy in some spots. People who are suffering from blotchy skin should avoid being overexposed to the sun.
The skin should be taken care of with a normal routine and with a gentle pH balancing soap that can help reduce the amount of pigment that is in the skin. People who have blotchy skin as a result of pregnancy should talk to their dermatologist about options that they can use to reduce the blotches while they are pregnant.