A foreskin that is tight or has a very small opening at the tip, preventing it from being retracted over the head of the penis
In phimosis, the foreskin is too tight or the opening at its tip is too narrow, so that it cannot be retracted (pulled back) over the head of the penis (the glans). Phimosis may make it difficult to clean the head of the penis thoroughly and, as a result, infections may occur under the foreskin (see Balanitis). In some cases, the condition also interferes with the normal flow of urine.
In most cases, phimosis is present at birth or becomes apparent during childhood, although it can occur at any age.
By the time a boy is 12 months old, it is usually possible to retract the foreskin. If it is not possible to pull a boy’s foreskin back over the glans by the age of 5, he has phimosis and probably needs treatment. The cause of the condition in babies and young children is unknown, but in older children and adults, it may result from scarring of the penile tissue due to recurrent episodes of balanitis.
The only symptom of phimosis may be an inability to pull back the foreskin, but this may be accompanied by:
Weak urinary stream.
Gradual ballooning of the foreskin when passing urine.
If bacteria become trapped behind the foreskin, balanitis and recurrent urinary tract infections may occur.
A complication of phimosis called paraphimosis may occur. In this condition, it is not possible for a foreskin that has been retracted to be rolled forwards again. The condition needs immediate medical attention because it constricts the flow of blood to the head of the penis, causing the area to become swollen and extremely painful.
Boys under the age of 5 will probably not need treatment because the condition is likely to improve by itself. If the condition has resulted in a urinary tract infection or difficulty passing urine, or if it occurs in adolescent boys or men, the doctor will probably recommend that surgical removal of the foreskin (see Circumcision) is carried out.
Paraphimosis needs immediate treatment. The doctor may ease the foreskin forwards by applying an ice pack to the penis, then gently squeezing the head. Alternatively, the doctor may make a small incision in the foreskin to enable it to be pulled forwards. Circumcision is often required to prevent recurrence.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.