The most common causes of vulvar pruritus are listed in Table 114-1. Patients with vaginitis often complain of itching. In candidal vulvovaginitis, which the majority of women experience at some point in their life, the vulva is erythematous, often with a sharp, scalloped border demarcating the area of involvement. “Satellite” lesions are characteristic, as is the cheesy discharge of the associated vaginitis (see Chapter 117). Primary cutaneous candidiasis of the vulva can also occur without vaginitis or discharge. It is more commonly seen in women with diabetes or those who are pregnant or obese. Intense vulvar inflammation also occurs with trichomonal infection, and, rarely, bacterial vaginosis may present with itching. Hidradenitis suppurativa, which is caused by inflammation or infection of the apocrine sweat glands found in the labia majora, can cause itching or burning and occasionally progresses to abscess or fistula formation.

Lesions of herpes genitalis are caused in most cases by herpes simplex virus type 2. The lesions, which begin as vesicles and progress to ulcers, cause burning, itching, and usually pain and tenderness of the vulva. Primary infection tends to be associated with fever, inguinal lymphadenopathy, and malaise. Vulvar warts caused by certain human papillomavirus (HPV) subtypes, called condyloma acuminata, are generally multifocal and appear on the labia minora or fourchette and perineum, where they may cause itching and occasionally vaginal discharge, although they are often asymptomatic. Vestibular papillomatosis is a normal mucosal variant manifested by clusters of pearly mucosal papules commonly mistaken for genital warts but differentiated by their being confined to the vestibule and not fused at the base. The umbilicated lesions of molluscum contagiosum may also be pruritic, although they too are often asymptomatic. This infection, which is generally self-limited in immunocompetent women, is also sexually transmitted. Dermatophyte lesions (tinea cruris) are a rare cause of itching in women; they are found more frequently in women using topical steroids to treat another vulvar condition.

Infestation with mites or lice can cause intense pruritus. Scabies produces papular lesions and itching, which may occur in several areas on the body, including wrists, finger webs, elbows, axillae, genitals, and buttocks. Pediculosis pubis (commonly known as “crabs”) is confined to areas covered by hair because eggs are deposited on the hair shafts (see Chapter 195).

Vulvar irritation caused by scratching, maceration, and chemical agents is common among women and girls of all ages. Deodorants, soaps, douching agents, bubble baths, and contraceptive foams may incite allergic reactions or chemical irritations, leading to itching. An active or inactive component of a topical medication may also be the inciting agent. The vulva may appear erythematous, and edema or secondary excoriations may be present. The precipitant may be inadequate or overly aggressive genital hygiene. A warm, moist environment, which promotes infection, can occur in patients who are obese or who wear tight-fitting pants or nylon underwear. Chafing fosters maceration of the mucosa in conjunction with the itching and scratching. Elderly women who experience urinary incontinence may be forced to wear pads, which can cause irritation. Younger women who shave their pubic hair are often bothered by pruritus from a secondary folliculitis.

Vulvar dermatoses are a large group of nonneoplastic papulosquamous lesions that occur on the vulva. Formerly referred to as vulvar dystrophy, these may cause pruritus in addition to other symptoms. Lesions may appear white when they are hyperkeratotic, but less than 5% are premalignant. Vulvar eczema may be either endogenous, due to atopy, or exogenous, secondary to an irritant or allergen (contact dermatitis). Chronic contact or irritant reactions of the vulva can cause persistent scratching and lichenification, leaving the vulva thickened and furrowed. The resultant leathery skin, termed lichen simplex chronicus, is the end stage of any chronic irritative or infectious disorder of the vulva that causes pruritus. Lichen sclerosis, a primary disorder of the vulva with an apparent autoimmune mechanism in some patients, is characterized by depigmentation around the vaginal introitus and perianal skin in a symmetric “keyhole” pattern, with pale atrophic epidermis with fine wrinkling or scaling on a whitened dermis. It can occur in women of any age, although it is most common after menopause. If untreated, it can lead to stenosis of the vaginal introitus (although the vagina itself is not involved) and atrophy or fusing of vulvar structures including the labia minora. Lichen sclerosis is associated with an increased risk (around 5%) of developing squamous cell carcinoma of the vulva, of a type not mediated by the HPV. Lichen planus, a less frequently seen primary vulvar disorder, may present in three forms: erosive, papulosquamous, and hypertrophic. The more common erosive form typically originates in the vaginal vestibule with erosion, white plaques and papules, and erythema extending into the vaginal canal with clearly demarcated borders. It may be associated with significant distortion and destruction of vulvovaginal structures. The papulosquamous form is characterized by “the five Ps”: pruritic purple polygonal papules and plaques, which occur on both oral and genital membranes. The hypertrophic form presents with rough, hyperkeratotic lesions of the perineum, which may resemble squamous cell carcinomas. Psoriasis may appear as moist red plaques with a silvery scale on the labia majora, although vulvar psoriasis may lack the typical scale. Seborrheic dermatitis of the vulva is uncommon but may present with scaling erythematous lesions of the vulva.