Sandbox:Zoon balanitis
Synonyms and keywords:Balanoposthite chronique circonscrite benigne a plasmocytes, Balanitis chronica circumscripta plasmacellularis, ZB, Zoon's vulvitis, Plasma cell vulvitis, Vulvitis circumscripta plasmacellularis

# Overview
Zoon's balanitis is a rare nonveneral idiopathic, chronic, benign inflammatory mucositis of genitalia. It was first described in the modern literature by Zoon, in 1952. The exact pathogenesis is not clearly known. It present as well circumscribed single or multiple, orange-red in colour with a characteristic glazed appearance and multiple pinpoint redder spots-"cayenne pepper spots" most commonly involving the glans penis.

# Historical Perspective
- In 1952, for the first time in medical literature, Zoon recognized a distinct entity in patients with chronic balanitis, named it as balanoposthite chronique circonscrite benigne a plasmocytes or balanitis chronica circumscripta plasmacellularis.
- In 1954, Garnier reported the similar lesion in vulva.
- In 1956, Nikolowski described the identical lesion in oral mucosa.
- In 1963, Kortnig described the idential lesion in conjuntiva.

# Classification
There is no established classification system for Zoon balanitis.

# Pathophysiology

## Pathogenesis
The exact pathogenesis is not clearly known, but following theories have been postulated:
- Accumlation of epithelial debris and secretions between foreskin and penis proximal to coronal sulcus, smegma,  poor genital hygiene, repeated local infections, hot and humid weather results in chronic physical irritation or subclinical trauma, which in turn results in skin lesion along the lines of the trauma.
- Chronic infection with Mycobacterium smegmatis and human papillomaviruses (HPV) was found to be associated with development of Zoon balanitis.
- Many theories, which include 1) local disturbance of circulation, 2) hypersensitivity response mediated by IgE class of antibodies, 3) extramedullary plasmacytic infiltrations that persists are expressions of occult multiple myeloma have been postulated, no supportive evidence have been found for these hypothesis.

### Histopathology
ZB has distinctive histopathological features, which include:

### Epidermal
- Epidermal changes include, early thickening, acanthosis and parakeratosis of epidermis, which is followed by atrophy, erosions and spongiosis.
- Scattered neutrophils can be present in superficial erosions of the epidermis.
- Spongiosis accentuation occurs in the lower half of the spinous zone.
- Subepidermal clefts, necrotic keratinocytes, and lozenge keratinocytes can be seen in the late stages of ZB.

### Dermal
- Dermal changes include  patchy lichenoid infiltrate of lymphocytes and plasma cells in papillary dermis, which are replaced by plasma cells, neutrophils, eosinophils, lymphocytes, and erythrocytes.
- Dermal  vascular dilatation with singular vertical or oblique orientation of proliferated individual vessels, is a characteristic feature  of ZB.
- In the later stages, upper dermis shows fibrosis which correlates well with subepidermal clefts, epidermal atrophy, and plasma cell infiltrates.

# Epidemiology and Demographics
Epidemiological and Demographic data of Zoon balanitis is scare.

# Screening
There is no established  screening guidelines for Zoon balanitis

# Natural History, Complications, and Prognosis

## Natural history
If left untreated, there is risk for malignant transformation.

## Complications
Complications of Zoon balanitis include:
- Phimosis
- Paraphimosis

## Prognosis
Prognosis is good with treatment.

# Diagnosis
Diagnosis is made on by obtaining detailed history, physical examination and reflectance confocal microscopy/dermoscopy findings:

## History and symptoms
Patients with Zoon balanitits could be asymptomatic or present with:
- Itching (pruritus) of the genitalia.
- Discomfort in urination(dysuria)
- Pain in the gential region
- blood stain discharge
- Difficult or painful sexual intercourse

## Physical examination
Physical examination findings include:
- Well circumscribed single or multiple, orange-red in colour with a characteristic glazed appearance and multiple pinpoint redder spots-"cayenne pepper spots"(please click here to view the image) most commonly involving the glans penis, but inner surface of prepuce and coronal sulcus may be involved.
- Though uncommon, lesions of Zoon balanitis can involve other sites which include labia minora in females, oral mucosa, conjunctiva, urethra, cheeks, and epiglottis have been described in literature.

## Laboratory findings

# Treatment

## General measures
Good hygiene which include retracting the foreskin regularly and gentle cleansing of entire glans, preputial sac, and foreskin were found effective in treating the diseases.

## Medical Therapy

## Surgery

## Photodynamic therapy
Photodynamic therapy, 5-aminolaevulinic acid (ALA) or methyl aminolevulinate (MAL), has been proposed for refractory lesions of ZB. ALA-PDT seems to be slightly better than MAL-PDT, with no long-term side effects observed.

## Miscellaneous therapies
Once-daily application fusidic acid cream for 8-16 weeks was effective in suppression and cure of ZB.

# Prevention

## Primary Prevention
Circumcision in males can help in reducing risk of having ZB.

## Secondary prevention
There is no secondary prevention measures.