Vitiligo Mais Shawabkeh Definition and epidemiology



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2-Vitiligo-mais-C3

Vitiligo


Mais Shawabkeh

Definition and epidemiology

  • it is an acquired common skin condition in which a patchy complete loss of epidermal melanocytes results in circumscribed depigmentation of the skin.
  • From the Latin word vitellus that means “Veal” (pale)
  • Prevalence 0.5–2% of the general population worldwide.
  • Peak incidence at 10–30 years but can occur in any age group.
  • Affect males and females equally.
  • Found in all races.
  • Family history in 30% of patients. in the generalized type.

Etiology

Unknown / Multifactorial :

  • Genetic predisposition (its inheritance is polygenic).
  • Autoimmune destruction of melanocytes: melanocytes are the target of a cell-mediated autoimmune attack or self-destruction as a result of an inability to remove toxic melanin precursors in the generalized type .
  • Oxidative stress (free radicals).
  • Intrinsic defects of melanocytes.
  • Triggering factors :

  • stress /sunburn
  • skin injury or trauma
  • Kӧbner phenomenon “isomorphic response’’: (the appearance of new skin lesions on previously unaffected skin secondary to trauma.)
  • Viruses
  • Industrial chemicals

Vitiligo types


Dermatomal distribution/ unilateral/ doesn’t cross the Medline
No clear segmental distribution/ no progression/ limited to one or few areas
In distal extremities and face
MC/Scattered patches that are widely distributed
Whole body (rare; more than 80% of skin is depigmented)
Localized
Generalized

Vitiligo patterns

1- Generalized/non-segmental

  • Common.
  • Mirrored
  • starts after the second decade.
  • most frequent in those with autoimmune diseases such as diabetes, thyroid disorders and pernicious anemia.
  • There is family history in 30% of patients.

2- Segmental
  • Rare
  • Restricted to one part of the body
  • earlier in life
  • is less likely to be associated with autoimmune diseases.

Clinical course

1- Generalized/non-segmental

  • Sharply defined, usually symmetrical white patches on the back of the hands, wrists, fronts of knees, neck and around body orifices. The hair of the scalp and beard may depigment too=Leukotrichia
  • Unpredictable course ,Lesions may remain static or spread.
  • Occasionally, repigment spontaneously from the hair follicles.

2- Segmental
  • Restricted to one part of the body, but not necessarily to a dermatome.
  • Responds poorly to most treatments
  • Spontaneous repigmentation occurs more often in this type.

Trichrome vitiligo

  • A variant of the generalized pattern.
  • Trichrome vitiligo consists of an intermediate zone of hypopigmentation(2) located between the depigmentation center(1) and the normal unaffected skin(3).

Differential diagnosis

  • Contact with depigmentaion chemicals: hydroquinones, substituted phenols in rubber industry.
  • Pityriasis(tinea) versicolor: fine scaling, patches tend to be paler than surrounding skin.
  • Idiopathic guttate hypomelanosis (a common acquired form of leukoderma that presents as small pale or white spots)
  • Nevus depigmentosus (a congenital nonprogressive hypopigmented macule or patch that is stable in its relative size and distribution throughout life).
  • Post inflammatory depigmentation: improves spontaneously, loss of pigment is partial.
  • Leprosy: must be excluded by sensory testing and general examination.
  • Pityriasis alba
  • Other topical diseases: Yaws, Pinta, Leishmaniasis.

Diagnosis

  • Usually, a clinical diagnosis.
  • If diagnosis is uncertain:
  • Wood lamp examination: The vitiligo lesions appear as well-defined blue-white areas + can help differentiate between hypopigmentation and depigmentation.
  • Dermoscopy: vitiligo lesions have a characteristic perilesional hyperpigmentation and telangiectasia
  • Skin biopsy and histology: Melanocytes are absent, perilesional lymphocytes may be observed.
  • Serological markers of autoimmune disease (e.g., thyroid function tests and antithyroid antibodies) once vitiligo is confirmed.

Wood lamp examination

Treatment

General measures :

  • Sunscreen (with a high sun protection factor helps in preventing the vitiliginous areas from burns)
  • Concealing makeup for cosmetic reason (camouflage)
  • Limited disease:

  • Topical steroids (betamethasone, mometasone, etc.)
  • Alternative: topical calcineurin inhibitors (tacrolimus, pimecrolimus)
  • Progressive or refractory disease:

  • Oral steroids
  • Narrowband ultraviolet B phototherapy
  • PUVA (psoralens and ultraviolet A light)
  • Localized irradiation of the skin can also be performed with laser
  • Surgery (grafts)
  • Finally, depigmentation should be considered in patients with greater than 50% cutaneous involvement who fail to respond or are unwilling to undergo treatment.


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