Paediatric Urology

3. PHIMOSIS AND OTHER ABNORMALITIES OF THE PENILE SKIN

The prepuce, or foreskin, of the penis is often a cause for concern to parents of young boys and physicians alike [21], with 10% seeking medical advice [22]. While there are some pathological abnormalities of the foreskin, these are in fact quite rare and must be discerned from physiological variations or developmental stages. In this chapter, we will highlight normal development, its variations and how to discern this from abnormal foreskin requiring treatment, and also provide various treatment options.

3.1. Terminology, epidemiology and pathophysiology

At birth, the foreskin can be retracted in 4% of boys. In 42% of neonates, the tip of the glans cannot be visualised. By the end of the first year of life, retraction of the foreskin behind the glandular corona is possible in approximately 50% of boys, increasing to 89% by the age of three years. Nonretractability of the foreskin can be a physiological phase that does not require treatment in the absence of symptoms, such as painful erections or balanitis.

Phimosis
In phimosis, the inability to retract the foreskin over the glans penis is due to a narrow ring in the prepuce. Several factors have been suggested to aid in the gradual dilation of this ring: histological changes in the prepuce, hormonal factors and stretching due to erections. While erections occur even antenatally, these may be insufficient to stretch the foreskin if it is relatively long, and therefore relative phimosis can be present for a prolonged period [23].

Epidemiological studies of the natural course of phimosis are difficult, as they are affected by treatment of a subgroup of subjects. Nonetheless, the incidence of phimosis is 9-20% in five- to 13-year-olds and just 1% in males aged 16 to 18 years [23,24].

Preputial adhesions
Another cause of nonretractability of the prepuce are adhesions of the foreskin to the glans. This must be distinguished from phimosis. Usually when adhesions are present, partial retraction is possible and the meatus can be visualised [24]. Adhesions are a physiological phenomenon of variable duration, present in 63% of six- to seven-year-olds and 3% of 16- to 17-year-olds without phimosis [24]. Progressive separation of the inner prepuce from the glans is associated with build-up of epithelial debris (smegma) and aided by penile erections. During this process, smegma can accumulate into nodules that may be mistaken for cysts. When released from between the skin layers, smegma can resemble purulent discharge, especially when mixed with urine. Focal erythema may also occur temporarily. In the absence of other signs of infection, this should not be confused with balanitis.

Once adhesions between the glans and inner prepuce are resolved, ballooning of the foreskin may also occur during voiding, particularly if the opening of the prepuce is still relatively narrow. Ballooning is not a sign of obstructed voiding and uroflows have been shown to be normal with ballooning [25]. Therefore, ballooning may be a physiological phase, and it should only be considered a problem in case of (recurring) balanitis.

Paraphimosis
In paraphimosis, the foreskin has been retracted and cannot be brought back down to cover the glans of the penis. In children, it is most likely due to manipulation, with an incidence reported to be as low as 0.2% [22]. The risk of paraphimosis is higher if relative phimosis is present. The narrow ring in the retracted prepuce may constrict the shaft at the level of the sulcus, leading to oedema of the glans and retracted foreskin. Impaired perfusion may lead to necrosis of the prepuce and ultimately of the glans. Paraphimosis must be regarded as a medical emergency requiring urgent treatment [26].

Balanitis/balanoposthitis
Balanoposthitis can be defined as erythema and swelling of the glans (balanitis) and/or foreskin (posthitis), with discharge of pus. It should not be confused with focal irritation due to retention of droplets of urine under the foreskin. Balanoposthitis may be seen in 6% of uncircumcised boys [22,27].

Balanitis xerotica obliterans
Balanitis xerotica obliterans (BXO) is a non-painful chronic inflammatory disease that may affect the glans, foreskin, meatus and urethra. As such, it is a genital form of lichen sclerosus et atrophicus [23]. Balanitis xerotica obliterans may lead to scarring, phimosis and urethral outflow problems. Histological analysis of the prepuces of children and adolescents undergoing circumcision for medical reasons shows signs of BXO in 35%-53% [28]; in boys younger than ten years, this is 17% [29,30].

Inconspicuous penis
The following are various types of concealed or inconspicuous penis, which should be differentiated from truly small penis such as micropenis, with abnormal size of the corporeal bodies or even aphallia:

• Buried penis and megaprepuce are congenital anomalies in which the skin is folded abnormally around the shaft. The opening of the prepuce can be narrow, prohibiting retraction similar to regular phimosis, but may also be normal. Buried penis can occasionally be due to abnormal prepubic fat distribution, which may be self-limiting with growth or weight loss.
• In webbed penis, the penoscrotal angle is abnormal due to the scrotum being attached high on the ventral side of the shaft.
• Trapped penis is an iatrogenic form of buried penis that may be caused by resection of too much skin during circumcision [31].

3.2. Classification and diagnostic evaluation

To determine which cases require treatment, phimosis should be divided into a physiological and pathological type. Physiological phimosis is most likely to resolve over time without intervention, whereas pathological phimosis may not.

In physiological phimosis, there is no sign of scarring and, upon retraction, the inner prepuce is seen bulging outward from the narrow ring in the prepuce (‘pouting’). In pathological or secondary phimosis, there is scarring; the narrow ring in the prepuce is fibrous, often white and thickened; and the inner layer of the prepuce is not seen coming out [32]. Balanitis xerotica obliterans is a special form of pathological phimosis.

The diagnosis of adhesions, phimosis and paraphimosis is made by physical examination alone and can differentiate between physiological variations or pathological abnormalities. If the prepuce is not retractable, or only partly retractable, and shows a constrictive ring upon retraction back over the glans penis, a disproportion between the width of the foreskin and the diameter of the glans penis must be assumed. In addition to the constricted foreskin, the inner prepuce may be adherend to the glans and/or frenulum breve.

Balanitis xerotica obliterans remains a histopathological diagnosis, as clinically discerning BXO from simple pathological phimosis by may be difficult, particularly to the untrained eye. Histopathological examination of resected foreskin is warranted due to the consequences of this diagnosis with regards to follow-up [33,34].

In buried penis, the shaft itself appears shorter upon inspection but is of normal size upon palpation, hence the name. In megaprepuce, the shaft may have a normal appearance, or it may resemble buried penis. The diagnosis is made based on the aspect of the penis during voiding. When the enlarged space between shaft and inner prepuce fills up with urine during voiding, this causes the entire penis to swell. Megaprepuce can be discerned from regular phimosis, in which only the tip of the penis may demonstrate ballooning. It may be helpful if caregivers show a photo or even video of the aspect of the penis during voiding.

3.3. Management

Hygiene
The foreskin should not be retracted for cleaning until this can be done easily. It should be stressed to parents/caregivers that forced retraction of a narrow foreskin may cause scar formation, resulting in secondary pathological phimosis [35]. Care should be taken to reduce the foreskin back down over the glans to prevent paraphimosis. Once the foreskin is retractable, this can be done regularly during bathing and becomes necessary for hygienic reasons starting in puberty. The production of smegma appears to increase at puberty, coinciding with the age at which most boys can retract their foreskin [32].

Conservative/medical management
Physiological phimosis and adhesions do not require treatment unless there are accompanying urogenital abnormalities. Conservative medical treatment is a valid option for primary pathological phimosis. Class 4 corticosteroid therapies were more effective over placebo and manual stretching [36]. Topical corticoid (0.05-0.1%) can be administered twice a day over a period of four to eight weeks with a success rate of > 80% [36-39]. A publication showed that lower class corticosteroids may be almost equally effective [40]. A recurrence rate of up to 17% can be expected [41]. Effectivity of topical corticosteroids is likely to be influenced by correct application, which must be directly onto the narrow ring under gentle retraction. Similarly, after finishing the corticosteroid treatment, recurrence should be prevented by continuing daily retraction of the prepuce [42]. While all types of phimoses may respond to corticosteroid treatment, the success rate may be lower in pathological phimosis. If BXO is suspected, consultation with a dermatologist should be considered [43].

Corticosteroid treatment has no systemic side effects, and mean blood cortisol levels are not significantly different from an untreated group of patients [44]. The hypothalamic-pituitary-adrenal axis was not influenced by local corticoid treatment [45]. However, if treatment is continued for too long or too much product is used, this may cause focal atrophy and vulnerability of the skin. In general, cream may be associated with dryness and irritation, due to the nature of the product compared to ointment. Adhesion of the foreskin to the glans does not respond to corticosteroid treatment [37].

Operative management
Circumcision for nonmedical reasons, such as routine circumcision for cultural, religious or hygienic considerations, is not discussed in this chapter.

Medical indications for surgical intervention for phimosis are recurrent balanoposthitis or symptomatic therapy-resistant phimosis. Simple ballooning of the foreskin during micturition is not an indication for surgery per se. Several indications for circumcision in the absence of symptomatic phimosis have been proposed. In boys with increased risk of urinary tract infections (UTIs) due to congenital upper tract abnormalities, circumcision may be performed to reduce the risk of UTIs [46-49]. Male circumcision significantly reduces the bacterial colonisation of the glans penis with regard to both non-uropathogenic and uropathogenic bacteria [50]. However, resolution of phimosis by corticosteroid treatment may have similar results, as it was also associated with substantial reduction in recurrent UTI in uncircumcised infants [51]. (See Chapter 12, Urinary tract infections in children, and Chapter 17, Vesicoureteric reflux).

Routine neonatal circumcision to prevent penile carcinoma is not indicated. A meta-analysis could not find any risk in uncircumcised patients without a history of phimosis [52].

The type of operative treatment of phimosis in children is dependent on the caregivers’ preferences and can be preputioplasty or circumcision. In preputioplasty, the objective is to preserve the prepuce while achieving a wider foreskin circumference with full retractability. Several surgical techniques have been described to achieve this goal: dorsal incision, partial circumcision, and trident preputioplasty, which combines two Z-plasties and Y-plasty [53,54]. The main disadvantage of preputioplasty is the inherent potential for recurrence of phimosis [55].

In circumcision, the prepuce is resected completely. Contraindications for circumcision are: an acute local infection and congenital anomalies of the penis, particularly hypospadias; buried penis and megaprepuce; epispadias; and congenital penile curvature, as the foreskin may be required for a reconstructive procedure [56,57].

When surgically correcting phimosis, additional issues should be addressed during the same session: adhesions are released, an associated frenulum breve is corrected by frenulotomy, and the meatus is calibrated with meatoplasty added if necessary.

Paraphimosis treatment
Treatment of paraphimosis consists of manual compression of the oedematous tissue with a subsequent attempt to retract the tightened foreskin over the glans penis [58,59]. If this manoeuvre fails, a dorsal incision of the constrictive ring is required. Following acute redressing of the foreskin, additional treatment is recommended to correct any anomalies that increase the chance of recurrence. Patients should be counselled regarding prevention of paraphimosis by correctly redressing their foreskin after retraction.

3.4. Complications

Complications following circumcision vary and have been reported in between 0-30% of all circumcisions [60]. Hung et al. found 2.9% complications in non-neonates during a five-year follow-up period; 2.2% were early (within 30 days after circumcision). Nonhealing wounds, haemorrhage, wound infection, meatal stenosis, redundant skin, non-satisfying cosmetic appearance and trapped penis all may occur [61]. The incidence of post-circumcision meatal stenosis is higher in boys with confirmed BXO compared to those who underwent circumcision for phimosis without BXO (20% vs. 6%) [33]. Overall, the risk of complications appears low when done by professionals in a medical setting.

3.5. Follow-up

Any preputial surgery requires early follow-up of four to six weeks after surgery. In case of BXO, prolonged follow-up is warranted and may involve a dermatologist. Balanitis xerotica obliterans is associated with meatal pathology (stenosis) after circumcision in up to 20% of boys [30,62,63].

3.6. Summary of evidence and recommendations for the management of phimosis