Freckles, also known as ephelides, are hyperpigmented spots that often appear on the face, neck, thorax, and arms. They are the result of an increase in the production of melanin in the skin. They usually appear in childhood, but decrease with age, and darken with sun exposure.
Freckles are common among the Caucasian population and more frequent in light-skinned and red-haired people, who tend not to tan, are more likely to suffer sunburn and sun spots, and are at an increased risk for malignant melanoma and skin cancers.
Freckles are associated with genetic variations in the IRF4 and MC1R genes. The MC1R gene contributes the most to red hair and fair skin. The number of parts depends on the number of variants of the MC1R gene.