A researcher in Germany has proposed a novel unifying theory that explains the molecular origin of rosacea in terms of climate adaption. He contends that the new concept may not only explain why the disorder’s known triggers can cause flare-ups, but is also consistent with known therapeutic activity against its signs and symptoms.1 According to Dr. Bodo Melnik of the University of Osnabrück, rosacea’s signs and symptoms may be the byproduct of a genetic mutation that helps people in northern areas compensate for insufficient production of vitamin D due to lack of sunlight during winter months. This may be comparable to the sickle cell mutation prevalent in hot climates, which may have developed as a protection against malaria. Dr. Melnik noted that individuals affected by rosacea are most commonly of northern European ancestry and consequently may have tended to be lacking in vitamin D, which helps regulate the production of an innate immune defense system substance called cathelicidin antimicrobial peptide (CAMP). This peptide helps defend against a host of bacterial pathogens and viral infections, and its deficiency may play a role in a variety of disorders. Read more at the National Rosacea Society.