A condition in which there is constriction in the tip of the foreskin resulting in inability to fully retract the foreskin over the glans penis. causes include balanoposthitis, balanitis xerotica obliterans, and untreated diabetes.

Phimosis (from Greek φίμωσις phimōsis 'muzzling') is a condition in which the foreskin of the penis cannot stretch to allow it to be pulled back past the glans. A balloon-like swelling under the foreskin may occur with urination...