I. OVERVIEW
A distinctive disorder of pigmentation in which the affected epidermis is devoid of one of its three main cell types (melanocytes) leading to a lack of melanin-based pigmentation in those affected areas.
A. Definition: acquired loss of pigmentation characterized histologically by complete absence of melanocytes in association with a total loss of epidermal pigmentation
B. Etiology
1. Exact pathogenesis is unclear.
2. Generalized symmetric form. Thought to be an autoimmune disease associated with antibodies (vitiligo antibodies) and cell-mediated cytotoxicity directed against melanocytes.
3. May be genetic (a predisposing factor); over 30% of affected individuals have reported vitiligo in a parent, sibling, or child; polygenic (i.e., not caused by a single gene defect) 4. Other theories include cytotoxic mechanisms, an intrinsic defect of melanocytes, oxidant–
antioxidant mechanisms, and neural mechanisms.
5. No definitive precipitating factor has been established; anecdotal correlation with the following environmental factors:
a. Psychological stress b. Physical trauma c. Pregnancy
d. Oral contraceptives
e. Sunlight and artificial ultraviolet light f. Illness
Note: These associations are frequently observed in a high percentage of normal individuals and have not been epidemiologically shown to occur more frequently in patients with vitiligo.
C. Pathophysiology
1. Caused by a loss of melanin from the epidermis.
2. A decrease in the number of melanocytes in affected areas.
3. Pigment loss may be localized, generalized, or universal.
D. Incidence
1. Worldwide prevalence of vitiligo is between 0.5% and 2%.
2. Up to 2.16% of children and adolescents are affected with vitiligo.
II. ASSESSMENT
A. History
1. Ask about initial presentation.
2. Ask about any somatic complaints or vision problems that may be associated with vitiligo.
a. Migraines
b. Decrease in hearing or pain with hearing (melanin may play important role in the structure and function of the auditory system)
3. Assess other diseases associated with vitiligo
a. Thyroid disease (hypo- and hyperthyroidism, Grave disease) b. Diabetes mellitus
c. Pernicious anemia d. Addison disease
e. Multiglandular insufficiency syndrome f. Alopecia areata
g. Melanoma
h. Lupus erythematosus i. Rheumatoid arthritis
4. Diseases that have been reported in patients with vitiligo a. Immune deficiency diseases
b. Multiple myeloma c. Dysgammaglobulinemia
d. Cutaneous T-cell lymphoma e. Thymoma
B. Clinical manifestations
1. Initial presentation and progression: variable; but genital, anal, axillary, and periorbital are often first areas affected.
2. Usually a depigmented macule or patch (1 to 3 cm) 3. Distinct margins
4. Variations in color and margins can occur (margin may be hyperpigmented, hypopigmented, or exhibit erythema, which is suggestive of an inflammatory process).
5. Face, joints, hands, and legs are the most commonly affected areas (Figure 17-1).
6. Mucous membranes may be affected.
7. Often symmetrical in presentation (Figure 17-2).
8. Classification of patterns of distribution a. Localized
(1) Focal: one or more macules in one area (2) Segmental: dermatomal pattern
(3) Mucosal: localized on mucous membranes
(4) “Lip-tip” pattern: involves skin around the mouth as well as on the distal fingers and toes; lips, nipples, and genitalia (tip of penis)
b. Generalized often remarkably symmetrical (1) Acrofacial: distal extremities and face (2) Vulgaris: diffuse presentation
(3) Mixed: combination of acrofacial and vulgaris
c. Universal-depigmented areas cover almost the entire body 9. Associated cutaneous findings
a. White and prematurely gray hair b. Alopecia areata
c. Halo nevi
C. Differential diagnosis 1. Piebaldism
2. Lupus erythematosus
3. Tinea versicolor (pityriasis versicolor) 4. Pityriasis alba
5. Lichen sclerosus et atrophicus 6. Cutaneous T-cell lymphoma 7. Sarcoidosis
8. Scleroderma
9. Postinflammatory pigmentary alteration (PIPA) 10. Tuberous sclerosis
11. Hypomelanosis of Ito 12. Incontinentia pigmenti
FIGURE 17-1. Vitiligo. (Copyright 2015 by the American Academy of Dermatology. All rights reserved.)
FIGURE 17-2. Vitiligo symmetry. (Copyright 2015 by the American Academy of Dermatology. All rights reserved.)
III. COMMON THERAPEUTIC MODALITIES
A. Goals of treatment
1. Restore normal function to epidermis 2. Cosmesis
B. Medical therapy: aimed at stimulating proliferation and migration of melanocytes 1. Topical steroids
a. Topical class 3 can be employed.
b. Applied daily for several months or longer.
c. If pigmentation not seen within 3 months, steroid should be stopped for approximately 6 months and then may be reinstituted or another treatment modality used.
2. Topical immunomodulators
a. Seem to be equally effective as topical steroids, especially when used in the face and neck region
b. Off-label indication for vitiligo
c. Black box warning for possible risk of cancer
3. Phototherapy (see Chapter 6, Phototherapy, for comprehensive discussion) a. Psoralen plus Ultra Violet A light (PUVA) either topical or systemic.
b. Topical or systemic PUVA is used two to three times weekly for several months; if no response, stop treatment for at least 6 months before trying again.
c. UVB narrowband (310- to 315-nm wavelength), two to three times weekly.
d. UVB narrowband therapy with excimer laser produces monochromatic rays at 308 nm to treat limited, stable patches of vitiligo, treated two to three times weekly, averaging 24 to 48 sessions.
4. Depigmentation
a. Used when there is involvement of more than 50% of the skin surface.
b. Monobenzone (monobenzyl ether of hydroquinone [MBEH]) is applied to skin twice daily until satisfactory depigmentation is achieved.
(1) Frequently requires strength of 20% to 40% to induce necrotic death of melanocytes
c. Informed consent from the patient as depigmentation is permanent and increases photosensitivity and pruritus.
C. Surgical therapy
1. Punch grafts: technique similar to hair transplantation a. Donor sites are pigmented areas of the skin.
b. Transplanted into depigmented areas of the skin.
c. Held in place with pressure dressings.
d. Repigmentation seen in 4 to 6 weeks after transplantation.
e. Residual pebbled skin may result, which can be cosmetically unacceptable.
2. Minigrafts: variant of the punch graft using smaller donor grafts to minimize pebbling
3. Suction blisters
a. Epidermal grafts are obtained by vacuum suction.
b. Blister roof is removed intact and grafted to depigmented site.
c. Good for large areas of depigmentation.
d. May be combined with phototherapy.
e. Repigmentation using this method may cause a mottled appearance.
4. Autologous cultures
a. Use autologous cultured melanocytes and keratinocytes from unaffected donor skin.
b. Applied to recipient sites that have had epidermis removed by suction, cryotherapy, or dermabrasion.
c. Color may be mottled or incompletely re-pigmented.
5. Autologous melanocyte grafts a. Variant of autologous cultures.
b. Injected into the depigmented site or used on superficially dermabraded skin.
c. Culturing melanocytes requires expertise and several months.
d. Spread of pigmentation is minimal.
6. Problems with surgical therapies a. Graft failure.
b. Donor sites may become depigmented (isomorphic response).
c. Risk of infection.
d. Risk of scarring in donor sites.
e. May be cost prohibitive.
Note: Five general options for management are sunscreens, cover-up, repigmentation, minigrafting, and depigmentation.