A flat circular spot on the skin about the size of the head of
a nail that develops after repeated exposure to sunlight, particularly in someone
of fair complexion. Freckles may be red, yellow, tan, light-brown, brown, or black.
They are always darker than the skin around them since they are due to deposits
of the dark melanin, a dark pigment.
T here are two basic types of freckles -- ephelides and lentigines. Ephelides
(singular: ephelis) are flat red or light-brown spots that typically appear during
the sunny months and fade in the winter. Lentigines (singular: lentigo) are small
tan, brown, or black spots which tend to be darker than an ephelis-type freckle
and which do not fade in the winter.
The sun is not the only factor that induces freckles. Heredity also influences
freckling, as witnessed by the striking similarity in the total number of freckles
on identical twins. Such similarities are considerably less marked in fraternal
twins. A gene for freckles has been mapped to chromosome 4q32-q34.
Freckles are harmless. They may sometimes be confused with more serious skin
problems. Conversely, more serious problems such as skin cancer may at times be
passed over as a mere freckle. Anyone who has one or more pigmented spots of which
they are not certain should be seen by a physician (or dermatologist). Effective
treatments are available to lighten or eliminate those freckles whose appearance
bothers their owners.
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