Characterized by lacy or net-like patches, mottled skin, or livedo reticularis, is caused by changes in the blood vessels found directly under the skin's surface, according to Tandurust. Common causes for these changes include fluctuations in body temperature, advanced age, certain blood disorders, coagulants, low platelet count, too much sun and certain medical conditions such as lupus and rheumatoid arthritis, according to Right Diagnosis.
Mottled skin usually appears in red patches on the trunk, arms and legs, which turn purple and dark brown over time. While these patches are more visible in light-skinned people, dark-skinned people are equally affected even if the signs aren't readily apparent. The signs of mottled skin are also more apparent in cold environments. There is no pain associated with this condition.
Treatment for mottled skin usually centers on treating the underlying disorder causing the symptoms. In some cases, topical creams and lotions may be used. However, DermNet NZ warns that there is no permanent treatment for the condition unless the underlying cause is reversed. Warming the area may help temporarily, but the affected blood vessels usually become more dilated over time, allowing more blood to pool under the skin's surface. In some cases, the mottling becomes permanent.