Eczema is the most common cause of balanoposthitis, and includes atopic, seborrheic, irritant and allergic contact dermatitis (4). Many of these constitute different forms of intertrigo. Atopic balanoposthitis often presents as erythematous, poorly demarcated and sometimes erosive mucosal changes (Figure 1). Irritant contact dermatitis, typically triggered by frequent use of soap, is particularly common and is often seen in atopic individuals. Seborrheic dermatitis is caused by hypersensitivity to the yeast Malassezia furfur, and its clinical presentation overlaps with other forms of eczema. The presence of flaky eczema in other seborrheic predilection areas (such as the scalp/face) increases the likelihood of seborrheic dermatitis. Allergic contact dermatitis differs from other forms of eczema and can lead to severe inflammation with erythematous and oedematous skin and/or mucous membranes. The medical history is directed towards potential allergens (latex, perfume and various preservatives). Allergies to cortisone preparations may also be found. In cases of repeated episodes of suspected (allergic) contact dermatitis, epicutaneous patch testing may be appropriate.
Psoriatic balanoposthitis can occur in isolation or simultaneously with other skin and nail changes. In circumcised patients, mucosal changes may have a classic psoriasis-like appearance, while erythematous and partly glazed mucosal changes may be observed in uncircumcised men. Maceration and secondary infection can also affect the clinical picture.
Candidal balanopostitis presents as somewhat non-specific, erythematous mucosal changes with soreness and itching. Erythematous papules, punctate erosions and/or whitish scaling increase the suspicion of fungal infection (Figure 2). Risk factors include diabetes mellitus, immunodeficiency, immunosuppressive treatment, antibiotic treatment, older age and excessive or poor hygiene (7). Candidal balanoposthitis is likely overdiagnosed, as less than 20 % of all balanoposthitis cases are due to candida infection (1).
Bacterial balanoposthitis can be caused by both aerobic and anaerobic bacteria. Aerobic balanoposthitis is a common condition and is often caused by staphylococci and/or streptococci (8). Common findings include variable inflammatory changes, including erythema, mild oedema and occasional suppuration. In anaerobic balanoposthitis, severe inflammation can be found with mucosal oedema, foul-smelling, superficial and weeping erosions, and in some cases inguinal lymphadenopathy. Anaerobic balanoposthitis can be caused by spirochetes, fusiform bacteria and Gram-negative rods, including anaerobic bacteria associated with bacterial vaginosis (7, 9).
Balanoposthitis can be caused by sexually transmitted infections, but this is not common. Mycoplasma genitalium, Trichomonas vaginalis, herpes simplex virus (HSV) and human papillomavirus (HPV) have been reported as causes of balanoposthitis. Primary syphilis infection can, in rare cases, present as erosive balanoposthitis (syphilitic balanitis of Follmann).
Lichen sclerosus is an inflammatory skin disease that causes scarring to the penis. The aetiology is unknown, but chronic irritation triggered by urine may be one of the causes (1). Initial presentation can include erythema, fissures and haemorrhagic mucosal changes. Patients often report itching. Chronic inflammation can lead to sclerotic mucosal changes, adhesions, phimosis and meatal stenosis (Figure 3). It also increases the risk of malignant transformation to cancer by 0–12.5 % compared to healthy individuals (1, 10). Patients should therefore be referred to a dermatologist if lichen sclerosus is suspected.
Lichen planus is an inflammatory condition that affects the skin, nails, genital and oral mucous membranes (1, 7). Well-demarcated, erythematous plaques with saw-toothed, white striae can be seen on the penis, and erosions may develop. If the patient has typical changes elsewhere on the body, the diagnosis is easily established. Oral lichen planus is particularly recognisable by the whitish and reticular, sometimes erosive, changes in the buccal mucosa. Genital lichen planus can be asymptomatic, and treatment is not always indicated if symptoms are minor (7).
Plasma cell balanoposthitis (Zoon's balanoposthitis) is a benign, inflammatory condition often seen as well-demarcated, orange-red glazed mucosal changes (Figure 4). Red-brown punctuate lesions ('cayenne pepper spots') due to hemosiderin deposition are typically observed. The inflammation can lead to adhesions between adjacent mucosal surfaces. The condition is primarily seen in older, uncircumcised men, likely due to chronic irritation triggered by urine and/or colonising microorganisms (1). Plasma cell balanoposthitis can be difficult to distinguish from (pre)malignant conditions. Diagnosis should be confirmed by biopsy, which shows a majority of plasma cells. Treatment combines hygienic, anti-inflammatory and antiseptic interventions. Circumcision is the most reliable curative treatment (2).
Circinate balanoposthitis is a post-infective, reactive condition that can be triggered by bacterial urethritis or enteritis in patients with a genetic predisposition (HLA-B27), and can occur in isolation or as part of reactive arthritis (1). The most important aspect is to identify the underlying cause and, if necessary, treat it. Chlamydia trachomatis is a potential cause, and testing for sexually transmitted infections is recommended. Circinate balanoposthitis often presents with a distinctive clinical picture characterised by greyish white, annular/geographic and coalescing mucosal changes. Patients often report mild itching and burning.
Non-specific balanoposthitis refers to cases with chronic or relapsing balanoposthitis symptoms where it is not possible to identify the cause(s) or achieve lasting remission (1). Topical corticosteroids have often been tried, typically combined with antifungal agents. Microbiological examination (including testing for sexually transmitted infections) is negative, and biopsy shows non-specific histopathological findings. In such cases, circumcision can be curative.