In the last few years, interest in vulvar disease has greatly increased. However, the relevant material has been scattered throughout the literature of various specialties, including dermatology, genitourinary medicine, gynecology, and pathology. The spectrum of involved specialties reflects the complexity of vulvar diseases and the necessity of a multidisciplinary approach to the study of the vulva.  In response to the various approaches of the specialists faced with treating vulvar disease, the World Health Organization, the International Society for the Study of Vulvar Disease, the International Federation of Gynecology and Obstetrics, and the International Society of Gynecological Pathologists have made an effort to standardize the nomenclature.
Some general anatomic, embryologic, and histologic findings of the vulva merit review. The vulva is the part of the female genital tract located between the genitocrural folds laterally, the mons pubis anteriorly, and the anus posteriorly. Embryologically, it is the result of the junction of the cloacal endoderm, urogenital ectoderm, and paramesonephric mesodermal layers. This hollow structure contains the labia majora, labia minora, clitoris, vestibule, urinary meatus, vaginal orifice, hymen, Bartholin glands, and Skene ducts. Different epithelia, from keratinized squamous epithelium to squamous mucosa, cover the vulva. The labia minora are rich with sebaceous glands but have few sweat glands and no hair follicles. The epithelium of the vestibule is neither pigmented nor keratinized and contains eccrine glands.
Benign vulvar disorders are a significant issue for patients. These disorders include vulvar atrophy, benign tumors, hamartomas and cysts, infectious disorders, and nonneoplastic epithelial disorders.  Infectious disorders include diseases caused by known transmissible agents, such as viruses, bacteria, fungi, and protozoa. They may first be seen by physicians of various specialties, including dermatologists and gynecologists, and often require a multidisciplinary approach.
Developmental abnormalities of vulva are generally rare. Vulvar atrophy may be related to advanced age or other disorders, but these abnormalities often represent an almost physiologic finding in the elderly.
Benign tumors of the vulva are relatively uncommon and may show nonspecific clinical features. Therefore, a biopsy is often needed to exclude a malignant neoplasm and to indicate proper treatment. Vascular neoplasms may also occur in the vulva and are similar to such lesions found elsewhere.
Nonneoplastic epithelial disorders include several inflammatory, ulcerative, and blistering disorders, as well as pigmentary changes involving the vulvar region.
Inflammatory diseases involving the vulvar region include the following:
- Lichen sclerosus
- Squamous cell hyperplasia (with and without atypia)
- Lichen simplex chronicus (localized neurodermatitis)
- Primary irritant dermatitis
- Allergic contact dermatitis
- Fixed drug eruption
- Atopic dermatitis
- Seborrheic dermatitis
- Reiter disease
- Lichen planus
- Lupus erythematosus
- Darier disease
- Aphthosis and Behçet disease
- Pyoderma gangrenosum
- Crohn disease
- Hidradenitis suppurativa
- Fox-Fordyce disease
- Plasma cell vulvitis
- Vulvar vestibulitis
Blistering diseases involving the vulvar region include the following:
- Familial benign chronic pemphigus (Hailey-Hailey disease)
- Bullous pemphigoid
- Cicatricial pemphigoid
- Pemphigus vulgaris
- Erythema multiforme
- Epidermolysis bullosa
Pigmentary changes involving the vulvar region include the following:
- Acanthosis nigricans
- Lentigo, lentiginosis, and benign vulvar melanosis
- Melanocytic nevus
- Postinflammatory hyperpigmentation
- Postinflammatory hypopigmentation
- Vulvar melanosis 
Benign tumors, hamartomas, and cysts involving the vulvar region include the following  :
- Mucous cysts
- Bartholin and Skene duct cysts
- Epidermal inclusion cyst
- Seborrheic keratosis
- Acrochordon (fibroepithelial polyp)
- Fibroma, fibromyoma, and dermatofibroma
- Pyogenic granuloma
- Heterotopic sebaceous glands and sebaceous gland hyperplasia
- Papillomatosis (papillary vulvar hirsutism)
- Schwannoma 
Congenital malformations involving the vulvar region include the following:
- Ambiguous external genitalia
- Congenital labial hypertrophy
- Labial adhesions
Clinical History and Physical Findings
Nonneoplastic epithelial disorders are discussed below.
Lichen sclerosus is commonly characterized by whitish lesions of the vulva. It is asymptomatic, but intractable pruritus can sometimes be present. Burning and pain are less likely manifestations. Clinically, the lesions are characterized by a wrinkled (“cigarette-paper”) or parchmentlike (shiny, delicate, pale) appearance of the skin that commonly extends around the anal area in a figure-8 or keyhole configuration
In late stages of the disease, normal architecture may be lost.  Additionally, atrophy and fusion of the labia minora, constriction of the vaginal orifice (kraurosis), synechiae, ecchymoses, fissures, and telangiectases may be noted. Squamous cell carcinoma develops in 3-6% of women affected by vulvar lichen sclerosus, which is therefore now regarded as a preneoplastic condition. [6, 66, 67] The presence and the duration of symptoms and the loss of vulvar architecture are not useful indicators of potential cancer risk.
Squamous cell hyperplasia
Squamous cell hyperplasia appears as ill-defined, single or scattered, asymmetrical, whitish, thickened, and sometimes verrucous plaques that may be accompanied by excoriations or fissurations that cause pain and soreness.
Itching is a common symptom. If hyperkeratosis is not prominent, lesions may appear as reddish plaques. The clitoris, labia minora, and inner aspects of the labia majora are more commonly affected.
Extensive lesions may result in stenosis of the vaginal introitus.
Lichen simplex chronicus (localized neurodermatitis)
Patients with lichen simplex chronicus present with a hyperkeratotic, usually ill-defined, grayish, thickened, and sometimes excoriated lesion, usually located over the labia majora and merging with normal skin.
Hyperpigmentation is common, and prominent skin markings are evident when the skin is involved. Itching is always present and may be intense.
Primary irritant dermatitis
Typical physical findings of primary irritant dermatitis include diffuse reddening of the involved skin with areas of excoriation. Secondary infection may occur.
An association with regional intertrigo, especially following mechanical irritation, may be observed
Chronic irritant dermatitis may lead to squamous cell hyperplasia.
Typically, intertrigo is characterized by erythema, local edema, oozing, maceration, and fissuring of the inguinal fold, sometimes accompanied by considerable odor. It may be associated with similar findings in other skin folds.
The surrounding skin may show reactive postinflammatory hyperpigmentation. Soreness and itching are common symptoms. Secondary candidosis may exacerbate intertrigo.
Allergic contact dermatitis
Physical examination often reveals dryness, scaling, excoriations, and, at times, ulceration. Itching is usually intense.
The clinical pattern may be subacute, with weeping and oozing, especially when bacterial superinfection occurs. Without treatment, allergic dermatitis can progress to squamous cell hyperplasia.
Fixed drug eruption
Fixed drug eruption appears as an erythematous and edematous plaque that frequently involves the genital area and typically resolves, leaving postinflammatory hyperpigmentation. 
The lesions are usually single at first presentation, but following reingestion of the drug, development of new elements may occur in addition to recurrence of the primary lesion.
The main complaint is burning, but some patients are asymptomatic or have mild pruritus.
Atopic dermatitis consists of a subacute or chronic, symmetric, and ill-defined eczematous rash, usually involving the labia majora and, less frequently, the labia minora and inner thighs.
The eruption is characterized by mild erythema, dryness, and fine scaling. Itching and burning are common symptoms.
Excoriation secondary to repeated scratching may cause bacterial superinfection with honey-colored crusting and, in chronic forms, lichenification. In some patients, the itch-scratch-itch cycle may gradually lead to development of lichen simplex chronicus.
When seborrheic dermatitis involves the vulva, the labia majora and mons pubis are primarily affected.
The lesions appear as dry-to-greasy scales superimposed on red-to-yellow brownish plaques and are often pruritic, extending to the gluteal cleft and thighs.