Phimosis may be congenital or acquired. The foreskin in young infants cannot be retracted, because at that gge it is adherent to the underlying glans. Wlen an attempt is made to retract the foreskin forcibly, splitting of the foreskin can occur and when healing takes place, scar formation and contracture follow, for example stenosis of the preputial orifice. Ballooning of the foreskin during micturition is a feature. Paraphimosis occurs when the phimotic prepuce is forcibly retracted and remains in that position. Oedema occurs and replacement is impossible. The swelling can become extensive, interfering with the circulation of the blood in the area.
The function of the prepuce or foreskin is a protective one, that is, it protects the glans from urine. During the first week of life, the infants's urine has a low urea concentration but this increases with the age of the child, leading to damage of the exposed glans and to meatal ulceration. It is therefore not desirable to retract the foreskin forcibly.