Paraphimosis is a condition in which the skin that normally folds over the penis—the foreskin—tightens and retracts, and cannot return to its normal position over the head of the penis. If not corrected, the penis will swell, and the blood flow to the head of the penis may be cut off, damaging the tissue.

Paraphimosis is caused by inflammation or infection of the foreskin, and may be associated with poor personal hygiene. Paraphimosis can only occur in uncircumcised men. Treatment may include circumcision and antibiotics.