What is Vitiligo
Vitiligo is a chronic, acquired, depigmenting, autoimmune disorder of the skin, resulting in the progressive loss of pigment-producing cells (melanocytes) which affect the color of the skin and hair. It manifests as milky-white patches of the skin, especially in those with dark skin, and it can be quite disabling from a cosmetic standpoint.
Epidemiology of Vitiligo
0.5–2% of people in the population have vitiligo. Between 20 and 24 years old is the typical onset age. Both sexes are equally affected, and there is a constant incidence across all races.
Causes of Vitiligo
Vitiligo is a multifactorial disorder related to both genetic and non-genetic factors. While environmental factors account only for 20% of vitiligo risk, genetic factors seem to account for 80% of it. The pathogenic hypotheses for vitiligo are variable and complex. The autoimmune destruction of melanocytes hypothesis suggests that autoantibodies are directed against several melanocyte antigens such as tyrosinase and tyrosinase-related proteins 1 and 2 (TYRP1 and TYRP2), which are crucial enzyme in the synthesis of melanin.
Clinical Features of Vitiligo
In most cases, vitiligo develops slowly. The most typical manifestation is a total loss of pigment in one or more macules or patches of the skin, which are characterized by their unique milky white color. Also, it typically has well-defined convex borders with possible hyper- or hypopigmented, red, or unaffected skin color borders. Vitiligo can be found in any region of the body; however, it tends to be more prevalent in sites of specific trauma, such as a cut, burn or abrasion, which is known as the Koebner phenomenon.
Classification of Vitiligo
Vitiligo classification is confusing. The following classification divides vitiligo into four general types. First, non-segmental vitiligo which tends to be bilateral and symmetrical. Second, segmental vitiligo which is usually unilateral and does not cross the midline. Third, mixed vitiligo, and lastly, unclassified vitiligo. These four classes are further divided into many subtypes.
Diagnosis of Vitiligo
The diagnosis of vitiligo is typically made clinically; no particular testing is necessary. However, there are numerous instruments, such as the wood’s lamp, dermoscopy, and skin biopsy, that assist in the diagnosis.
Management of Vitiligo
There is no cure for vitiligo. The aim of treatment is to stop the progression of the disease and to achieve a satisfactory repigmentation. Minimizing skin injury and sun protection are important measures to limit disease progression. Topical treatments are commonly used which include corticosteroids, calcineurin inhibitors, and in some cases, JAK inhibitors cream. Phototherapy is also widely used, options include narrowband UVB, psoralen photochemotherapy(PUVA) and excimer laser which is useful in localized lesions of vitiligo. Systemic treatment may be needed, including systemic steroids, methotrexate, ciclosporin, and mycophenolate mofetil. Additionally, depigmentation therapy may be used in widespread disease with only a few areas of normally pigmented skin.
Outcome of Vitiligo
There are some predictors that suggest an active disease, including peripheral hypopigmentation, confetti-like depigmentation, ill rather than well-defined borders, and the Koebner phenomenon.
Vitiligo’s clinical course is incredibly variable. Vitiligo typically grows slowly over several months, then goes dormant for years. It can be challenging to manage.
Mohammed Alahmadi, medical student.
Maee Barakeh, medical student
Bolognia textbook of dermatology