A<unk>  is an infected tract under the skin, usually between the buttocks, in the natal cleft. It is usually a small cavity containing a tuft of hair and possibly can be oozing pus.
A<unk>  tract is a small abnormal channel (like a small tunnel) in the body. A tract typically goes from the source of infection, often deep within the body, to the skin's surface. A<unk>  can be developed after an abscess is cleared (by itself or by medical treatment), then one of more of the small openings (tracts) join the cavity to the skin surface. This is not always the case as some people can develop a<unk>  without ever having a<unk>  abscess.
Anyone can develop a<unk> . However, it mainly affects people between the age of 16 and 30.
Pilonidal sinus
Cauliflower ear
Ranula
Cumulus oophorus
Lacrimal canaliculi
Ear canal
Nasolacrimal duct
Lacrimal bone