A comedo is a clogged hair follicle (pore) in the skin. Keratin (skin debris) combines with oil to block the follicle. A comedo can be open (blackhead) or closed by skin (whitehead) and occur with or without acne. The word "comedo" comes from the Latin comedere, meaning "to eat up", and was historically used to describe parasitic worms; in modern medical terminology, it is used to suggest the worm-like appearance of the expressed material.The chronic inflammatory condition that usually includes comedones, inflamed papules, and pustules (pimples) is called acne. Infection causes inflammation and the development of pus. Whether a skin condition classifies as acne depends on the number of comedones and infection. Comedones should not be confused with sebaceous filaments. Comedo-type ductal carcinoma in situ (DCIS) is not related to the skin conditions discussed here. DCIS is a noninvasive form of breast cancer, but comedo-type DCIS may be more aggressive, so may be more likely to become invasive. Causes
Oil production in the sebaceous glands increases during puberty, causing comedones and acne to be common in adolescents. Acne is also found premenstrually and in women with polycystic ovarian syndrome. Smoking may worsen acne.Oxidation rather than poor hygiene or dirt causes blackheads to be black. Washing or scrubbing the skin too much could make it worse, by irritating the skin. Touching and picking at comedones might cause irritation and spread infection.
The most frequent adverse events leading to patch discontinuation were: nausea and/or vomiting (2.4%), application site reaction (1.9%), breast discomfort, engorgement or pain (1.9%), headache (1.1%), and emotional lability (1.0%).The most frequent adverse events reported while using the Ortho Evra / Evra patch were: breast discomfort, engorgement or pain (22%), headache (21%), application site reaction (17%), nausea (17%), upper respiratory tract infection (10%), menstrual cramps (10%), and abdominal pain (9%).Breakthrough bleeding and/or spotting while using the Ortho Evra / Evra patch was reported by: 18% in cycle 1, 12% in cycle 3, 8% in cycle 6 and cycle 13. Breakthrough bleeding (requiring more than one pad or tampon per day) was reported by: 4% in cycle 1, 3% in cycle 3 and cycle 6, and 1% in cycle 13.Overall, side effects that tend to go away after two or three months include bleeding between periods, breast tenderness, and nausea and vomiting. Symptoms that may last longer include skin irritation around the area where the patch is placed and a change in the womans sexual desires.Additional side effect information is provided in the Ortho Evra label information and the Evra Summary of Product Characteristics (SPC) and PIL.