Vitiligo is a condition where there is a gradual loss of pigmentation in the skin, hair, and mucous membranes due to the absence of melanocytes in those areas.
General Characteristics
Definition & overview
Vitiligo is a chronic (long-lasting) autoimmune disorder that causes patches of skin to lose pigment or color, due to absence of functional melanocytes secondary to melanocyte destruction.
Melanocyte destruction in vitiligo seems to have an autoimmune basis, resulting from a combination of genetic and environmental triggering factors
Vitiligo is epidemiologically associated with other autoimmune diseases, including autoimmune thyroid disease and adult-onset type 1 diabetes mellitus
Epidemiology
Vitiligo is the most common depigmenting disorder. The global prevalence is 0.5–1% and there is probably no gender or ethnic variation.
Vitiligo affects people of all skin types, but it may be more noticeable in people with brown or Black skin.
Onset of the disease can be at any age but in the majority of cases it becomes apparent in the third decade of life.
Pathophysiology & Role of genetics in the development of Vitiligo
Vitiligo is a multifactorial disease with genetic and non-genetic causes. The exact pathophysiology of vitiligo is not understood.
1) An autoimmune theory suggests that alterations in cellular or humoral immunity → melanocyte destruction. Possibly secondary to cytotoxic activity of autoreactive T-cells against melanocytes.
- Vitiligo is associated with autoimmune diseases in 20–30% of cases. The most common associations are with Hashimoto’s thyroiditis, Grave’s disease, rheumatoid arthritis, psoriasis, type 1 diabetes (usually adult-onset), pernicious anemia, systemic lupus erythematosus, and Addison’s disease.
2) Family history (heredity): There is a genetic component because 30% of patients have a positive family history and vitiligo has been reported in monozygotic twins.
Genetic vitiligo (GV) is most often a gradually progressive disorder and is unresponsive to treatment. However, some cases do stop progressing. GV complications are long duration, Koebner phenomenon, leukotrichia, and mucosal involvement.
3) A trigger event, such as stress, severe sunburn or skin trauma, such as exposure to a chemical – can trigger vitiligo or make it worse.
Connection between diabetes and Vitiligo
Vitiligo is much more prevalent in those with diabetes mellitus. A 2009 study of 50 patients with type 1 diabetes reported that 4% of subjects had vitiligo.
Coinciding vitiligo and type 1 diabetes mellitus may be associated with endocrine autoimmune abnormalities of the gastric parietal cells, adrenal, or thyroid.
Clinical features & Types of Vitiligo
Vitiligo is characterized by Well-circumscribed, depigmented, and asymptomatic macules/patches, that can affect the skin on any part of the body. particularly in acrofacial regions, as well as affecting areas of repeated friction such as the elbows, knees and ankles. It can also affect hair and the inside of the mouth.
- Most commonly, the distribution of lesions is symmetrical. The discolored areas usually enlarge over time, either slowly, or rapidly (Köebner phenomenon)
The Koebner phenomenon is observed in some cases, with occurrence of vitiligo in areas of skin trauma, such as surgery.
People with vitiligo can also develop:
- Low self-esteem or a poor self-image from concerns about appearance, which can affect quality of life.
- Uveitis, a general term that describes inflammation or swelling in the eye.
- Inflammation in the ear.
Progression of the disease
Progression of vitiligo is unpredictable; it is usually gradually progressive but may extend rapidly over a period of several months and then remain quiescent for many years.
- Sometimes the patches stop forming without treatment. In most cases, pigment loss spreads and eventually involves most of the skin. and Occasionally, the skin gets its color back.
Types of Vitiligo
Out of several subtypes, generalized vitiligo is most common.
- Universal (>80% of skin; rare): With this type, the discoloration affects nearly all skin surfaces.
- Generalized (most common type): Many parts of the body. the discolored patches often progress similarly on corresponding body parts (symmetrically).
- Segmental vitiligo (primarily in children): The segmental subtype of vitiligo is much less common and happens when the white patches are only on one segment or side of your body, such as a leg, one side of the face, or arm. This type of vitiligo often begins at an early age and progresses for 6 to 12 months and then usually stops.
- localized (focal): One or only a few areas of the body.
- Acrofacial (The face and hands): With this type, the affected skin is on the face and hands, and around body openings, such as the eyes, nose and ears.
Diagnosis & Treatment of vitiligo
How vitiligo is diagnosed?
Examination with the aid of a Wood’s light is helpful to confirm the diagnosis and delineate extent of disease.
Treatment options for vitiligo
Although there is no cure for vitiligo, treatments can be very effective at stopping the progression and reversing its effects, which may help skin tone appear more even. Dermatological therapy attempts to reduce T-cell response and induce melanocyte migration and regeneration.
1) First line treatments: Corticosteroids with ultraviolet B or calcineurin inhibitors or systemic psoralen and ultraviolet A (PUVA) light are first-line treatments.
2) Other options: Calcipotriol, topical PUVA, excimer laser, corticosteroid pulse therapy, and surgical melanocyte grafting are some of the treatment options.
3) In those patients with extensive vitiligo and only a few residual areas of pigmentation, skin bleaching with laser therapy (e.g. Q‐switched alexandrite 755 nm, Q‐switched ruby 694 nm) or creams (e.g. 20% monobenzylether of hydroquinone) considered.
4) Use of sunscreen is recommended but also controversial because of ultraviolet B stimulation of melanocytes and the possibility of repopulation, as well as photo-adaptation of vitiligo-affected skin.
Moderate exposure to sun is recommended.
5) The psychosocial impact of vitiligo can be substantial, and patient support groups are available.