Vitiligo is characterized by asymptomatic milk-white patches with no evidence of texture change. At times, the distinction between the depigmentation of vitiligo and the hypopigmentation of other white patches can be difficult to confirm, particularly in light-complexioned individuals. A Wood light differentiates these two states, with depigmentation appearing bright white and verifying the diagnosis of vitiligo, whereas hypopigmentation shows little difference compared to surrounding unaffected. Also, vitiligo shows no crinkling, roughness, scale, lichenification, smoothness, or shininess (Figs. 8-1, 8-2, 8-3). The pigment loss can be patchy or extensive and confluent. Patients often present with extragenital lesions that are more distinct when surrounding skin darkens from tan.

There is a predilection for body sites that are often irritated or injured (called the isomorphic response, previously called Koebner phenomenon). This helps to explain the typical locations such as the external genitalia, skin over the metacarpal joints, and around the mouth. This also helps to explain why vitiligo sometimes occurs in the setting of an underlying skin disease such as lichen simplex chronicus (LSC) or lichen sclerosus. Although vitiligo produces no pruritus or pain, the scratching of conditions such as LSC can precipitate vitiligo. Lichen sclerosus especially is known to occur in association with vitiligo, even in association with extragenital vitiligo (Fig. 8-4). Then, the lichenification, excoriations, and texture change of LSC in a setting of vitiligo can confuse the examiner who is expecting no texture change or symptoms with vitiligo.

The hair within depigmented patches sometimes loses their pigment (poliosis) (Fig. 8-5). The last melanocytes to be disappear and the first to reappear are at the base of hair follicles; vitiligo often exhibits skin-colored follicular macules within a patch of depigmentation (Fig. 8-6). The border of the depigmented skin is sometimes hyperpigmented, and sometimes there are hypopigmented
macules in addition to hyperpigmentation and depigmentation (Fig. 8-7). Widespread vitiligo occasionally can be difficult to differentiate from a hyperpigmented condition (Fig. 8-8), where the normal skin color can be misinterpreted as hyperpigmentation in light-complexioned patients. At times, even the patient believes he or she has brown patches instead of normal skin color in a background of depigmentation.

Patients with generalized vitiligo exhibit an increase in other autoimmune diseases, especially thyroid disease, and have more circulating autoantibodies in general.

Vitiligo is a cosmetic issue only. However, this condition can be very upsetting to some patients, especially those in Eastern countries.¹ And, any disfigurement of the genitalia can be upsetting to many patients, resulting in sexual dysfunction and other stresses.^8,9 Because our options for successful repigmentation of vitiligo are limited at this time, the provider should be very aware of the psychological ramifications for some patients, and address or refer those individuals.

Some patients are not especially bothered by their genital vitiligo, and no therapy is required for those people. For those who wish to pursue treatment, there are medical and surgical options, although in practice, finding providers who offer the surgical options in the United States is extremely difficult. Ultraviolet light in combination with topical agents have been reported useful, but this increases the risk of squamous cell carcinoma, especially on anogenital skin. Most clinicians begin with topical therapies, especially superpotent corticosteroids, taking care to follow carefully for atrophy and other side effects.¹⁰ One method is a trial of a potent topical corticosteroid (ie, clobetasol propionate or halobetasol propionate for no longer than 8 weeks in a cycle). When there is some repigmentation with this therapy, cycles of a corticosteroid can be used, such as 6 weeks on and 6 weeks off. Care must be taken, particularly in the genitocrural folds, inner upper thighs, and scrotum, as these areas are susceptible to steroid atrophy. Many providers also use a topical calcineurin inhibitor, tacrolimus (Protopic) or pimecrolimus (Elidel) twice a day, often in combination with the topical corticosteroid.¹¹ These expensive medications are often not covered by insurance for this purpose but have no side effects of atrophy or steroid dermatitis.⁵ They may sting with application, and they are black-boxed by the U.S. Food and Drug Administration for the unlikely events of squamous cell carcinoma and lymphoma. Topical calcipotriol, a vitamin D analog, is sometimes used as well.^12,13

Intravenous (not oral) corticosteroid pulses have been reported useful.¹⁴ The biologic therapies with Janus kinase inhibitors have shown promise as well.¹⁵ More aggressive therapies that are not routinely used include epidermal grafts and melanocyte-keratinocyte transplantation.^16,17 Although dermabrasion is usually used only to prepare recipient skin for grafts, use of dermabrasion alone with adjuvant topical 5-fluorouracil¹⁸ and tacrolimus¹⁹ have been shown useful. Anything that damages the skin runs the risk of worsening of the vitiligo due to the isomorphic response.

Phototherapy has been used for years for vitiligo, but it is a poor choice in the anogenital area due to the increased risk of squamous cell carcinomas that occur with chronic ultraviolet therapy. The 308-nm excimer laser has been used but appears to be less effective than calcineurin inhibitors.²⁰ There are early trials using fractional CO₂ laser alone and in combination with other therapies. A summary of a systematic Cochrane review of management for vitiligo shows that data are derived from poorly designed trials and concluded that only corticosteroids and phototherapy can be shown from data to show benefit.²¹

People with vitiligo that is widespread or cosmetically disfiguring can be treated by depigmentation therapy, where 20% monobenzylether of hydroquinone is used to depigment normal skin so that the skin does not show patches of discoloration. This medication must be compounded and has a fairly high risk of contact dermatitis. Support and reassurance are generally the most effective course for genital vitiligo.

Injury or inflammation of the skin can produce either hyperpigmentation or hypopigmentation. Hypopigmentation can be mild or marked, and usually, but not always, there is a history of a preceding event. The color changes are more marked in people with a natural darker complexion. Poorly demarcated hypopigmentation occurs in the distribution of the preceding inflammation or injury (Fig. 8-9). The loss of pigment is often very subtle, and unless the cause of the inflammation is ongoing, the skin should show only hypopigmentation, without texture changes or scale. When the injury is severe, such as a chemical burn, the borders may be well demarcated.

There is no treatment for postinflammatory hypopigmentation other than treatment of or prevention of further dermatosis or injury. The normal skin pigmentation returns spontaneously to most with time.

The most common presentation of LS is in the postmenopausal woman. However, this condition can occur at any time, including childhood. The classic presenting symptom is that of pruritus that can be excruciating, often associated with pain from erosions in the fragile skin due to rubbing and scratching or minor, otherwise inconsequential, trauma, including sexual activity. Often, lichen sclerosus is asymptomatic until an event such as a yeast infection produces symptoms that initiate irritation with resulting rubbing and scratching that perpetuates the inflammation and injury.

Constipation is a common presenting complaint in prepubertal girls, because lichen sclerosus around the rectal canal causes fissuring and painful defecation with consequent anal retention. Perianal involvement almost never occurs in boys and men.

The classic findings of lichen sclerosus consist of white papules and plaques that are usually fairly well demarcated (Fig. 8-10). The clitoris is often puffy, white, and smooth, whereas the surrounding skin characteristically is white and crinkled. In women, lichen sclerosus often first and most prominently affects the clitoral area and the perineal body (Fig. 8-11). The entire modified mucous membranes and perianal skin become involved in some women, which many clinicians visualize as a figure-of-8 pattern (Fig. 8-12). In the male, LS occurs on the glans and prepuce
of the penis and less commonly the shaft (Figs. 8-13 and 8-14). Occasionally, the scrotum is affected (Fig. 8-15).

Although hypopigmentation occurs in many skin diseases, the texture of lichen sclerosus is a strong diagnostic clue. The skin surface classically shows fine crinkling, a reliable sign of lichen sclerosus (Fig. 8-16). At times, the skin can be shiny and smooth, waxy, or hyperkeratotic
and rough, but there are always texture changes (Figs. 8-17, 8-18, 8-19, 8-20). Sometimes, rather than plaques, small discrete papules occur, often coalescing into plaques (Fig. 8-21). Ecchymosis is extremely suggestive of lichen sclerosus (Figs. 8-12, 8-22, 8-23). These ecchymoses can be mistaken for evidence of abuse in young girls. Additional signs include erosions or ulceration due to the fragility of lichen
sclerosus. Hyperkeratotic plaques occur at times; sometimes as a result of rubbing and scratching, and sometimes spontaneously, which is worrisome for incipient differentiated vulvar intraepithelial neoplasia (dVIN or squamous cell carcinoma in situ) (Fig. 8-23).

In young boys, lichen sclerosus often presents with phimosis, and LS is a major cause of medical circumcisions. The lichen sclerosus is often unrecognized until the excised prepuce is examined histologically. White papules occur on the glans and ventral foreskin, producing the same white, fragile plaques that may exhibit purpura. The shaft can be involved as well.

Scarring is usual in more advanced disease; in women, this is manifested by resorption of the labia minora and scarring of the clitoral hood to the clitoris, with eventual sealing of the clitoral hood, or prepuce, concealing the glans clitoris underneath (Fig. 8-24). At times, the pocket formed under the clitoral hood becomes impacted with keratin debris of trapped keratinocytes shed from the surface of the epithelium, forming a pseudocyst (Fig. 8-25).
Although usually asymptomatic, these pseudocysts occasionally produce discomfort from distention and decrease sensitivity of the clitoris because of the accumulated keratin between the clitoris and the skin surface. Rupture of the pseudocyst produces a brisk foreign body response, resulting in a painful, red nodule that may drain keratin and purulent material.

Midline adhesions result in introital narrowing. Lichen sclerosus usually spares the mucosal surface of the vagina, and this is sometimes discussed as a differentiating feature from lichen planus, with only four reported cases in the literature. However, this author (LE) has six patients with biopsy-proven vaginal lichen sclerosus, so vaginal LS clearly occurs more often than realized.^{8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26} This usually, but not always, occurs overlying an exposed, prominent cystocele or rectocele in an area of squamous metaplasia. But, unlike occurring with lichen planus, there are no reported cases of narrowing of the vagina itself occurring with lichen sclerosus (Fig. 8-26).