Multiple open<unk> nes at the nasolabial fold and the alar of the nose<unk> nes are associated with the pilosebaceous unit, which includes a hair follicle and sebaceous gland. These units are mostly on the face, neck, upper chest, shoulders, and back. Excess keratin combined with sebum can plug the opening of the follicle. This small plug is called a microcomedo. Androgens increase sebum (oil) production. If sebum continues to build up behind the plug, it can enlarge and form a visible<unk> . A<unk> ne may be open to the air ("blackhead") or closed by skin ("whitehead"). Being open to the air causes oxidation, which turns it black. Cutibacterium acnes is the suspected infectious agent in acne. It can proliferate in sebum and cause inflamed pustules (pimples) characteristic of acne. Nodules are inflamed, painful, deep bumps under the skin.<unk> nes that are 1 mm or larger are called macrocomedones. They are closed<unk> nes and are more frequent on the face than neck. Solar<unk> nes (sometimes called senile<unk> nes) are related to many years of exposure to the sun, usually on the cheeks, not to acne-related pathophysiology.
Comedo
Wart
Scruple 
Purell
Superbill
Serenic
Rosette 
Aidoc