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. In teenagers and adults, it may result in pain during an erection, but is otherwise not painful. Those affected are at greater risk of inflammation of the glans, known as balanitis, and other complications.
In young boys, it is normal not to be able to pull back the foreskin at all. Over 90% of cases resolve by the age of seven, although full retraction is still prevented by preputial adhesions in over half at this age. Occasionally, phimosis may be caused by an underlying condition such as scarring due to balanitis or balanitis xerotica obliterans. This can typically be diagnosed by seeing scarring of the opening of the foreskin.
Typically, the condition resolves without treatment by the age of 18. Efforts to pull back the foreskin during the early years of a young male's life should not be attempted. For those in whom the condition does not improve further, time can be given or a steroid cream may be used to attempt to loosen the tight skin. If this method, combined with stretching exercises, is not effective, then other treatments such as circumcision may be recommended. A potential complication of phimosis is paraphimosis, where the tight foreskin becomes trapped behind the glans.
Signs and symptoms
At birth, the inner layer of the foreskin is sealed to the glans penis. The foreskin is usually non-retractable in early childhood, and some males may reach the age of 18 before their foreskin can be fully retracted.
Medical associations advise not to retract the foreskin of an infant, in order to prevent scarring. Some argue that non-retractability may "be considered normal for males up to and including adolescence." Hill states that full retractability of the foreskin may not be achieved until late childhood or early adulthood. A Danish survey found that the mean age of first foreskin retraction is 10.4 years.
Rickwood, as well as other authors, has suggested that true phimosis is over-diagnosed due to failure to distinguish between normal developmental non-retractability and a pathological condition. Some authors use the terms "physiologic" and "pathologic" to distinguish between these types of phimosis; others use the term "non-retractile foreskin" to distinguish this developmental condition from pathologic phimosis.
In some cases a cause may not be clear, or it may be difficult to distinguish physiological phimosis from pathological phimosis if an infant appears to have discomfort while urinating or demonstrates obvious ballooning of the foreskin. However, ballooning does not indicate urinary obstruction.
In women, a comparable condition is known as "clitoral phimosis", whereby the clitoral hood cannot be retracted, limiting exposure of the glans clitoridis.
Severity
Score 1: full retraction of foreskin, tight behind the glans. Score 2: partial exposure of glans, prepuce (not congenital adhesions) limiting factor. Score 3: partial retraction, meatus just visible. Score 4: slight retraction, but some distance between tip and glans, i.e. neither meatus nor glans can be exposed. Score 5: absolutely no retraction of the foreskin.
Cause
There are three mechanical conditions that prevent foreskin retraction:
The tip of the foreskin is too narrow to pass over the glans penis. This is normal in children and adolescents.
The inner surface of the foreskin is fused with the glans penis. This is normal in children and adolescents but abnormal in adults.
The frenulum is too short to allow complete retraction of the foreskin (a condition called frenulum breve). Pathological phimosis (as opposed to the natural non-retractability of the foreskin in childhood) is rare, and the causes are varied. Some cases may arise from balanitis (inflammation of the glans penis).
Lichen sclerosus et atrophicus (thought to be the same condition as balanitis xerotica obliterans) is regarded as a common (or even the main) cause of pathological phimosis. This is a skin condition of unknown origin that causes a whitish ring of indurated tissue (a cicatrix) to form near the tip of the prepuce. This inelastic tissue prevents retraction.
Phimosis may occur after other types of chronic inflammation (such as balanoposthitis), repeated catheterization, or forcible foreskin retraction.
Phimosis may also arise in untreated diabetics due to the presence of glucose in their urine giving rise to infection in the foreskin.