Vitiligo is a skin condition characterised by the emergence of white patches on variously extensive areas of the body. It's not uncommon for this dermatosis to be confused with other pathologies. What about leucoderma? How can it be differentiated from vitiligo? Let's explore these questions together.
Leucoderma and Vitiligo: Are there differences between these conditions?
Published on December 2, 2024, by Pauline, Chemical Engineer — 4 min of reading
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How to differentiate vitiligo from leucoderma?
Leucoderma is a term derived from the ancient Greek leukós, meaning white, and dérma, referring to the skin. The etymology of this term allows us to understand that it is related to a white discolouration of the skin. According to the dictionary of the National Academy of Pharmacy, leucoderma is defined as follows: "Hypopigmentation or depigmentation of areas of the epidermis due to a deficiency or absence of melanin. It can be congenital, as in albinism, or acquired, for example in leprosy, psoriasis, syphilis, vitiligo or the scar tissue of a wound."
Vitiligo is a specific form of leucoderma characterised by a selective loss of melanocytes.
There are several types of leucoderma, which can result from various causes. Leucoderma can thus be the consequence of a lack of melanin pigment, following a decrease in the number of melanocytes or a defect in the synthesis or transfer of melanin, localised vasoconstriction, a deposit of white substance such as cutaneous calcification for example, tension exerted on the epidermis, by a cyst wall notably, a skin infarction such as in white atrophy or Degos disease or even a keratosis as in warts or molluscum contagiosum. Leucodermas can be diffuse or circumscribed. Based on this criterion and the age at which they appear, it is possible to differentiate them and determine if it is a case of vitiligo, as shown by the decision tree below.
Diagnostic approach to leukoderma based on the diffuse or localized nature of the lesion and the age of onset.
Source: BAHADORAN P. & LIPSKER D. Leucodermies. EMC - Dermatology - Cosmetology (2005).
Vitiligo arises from a reduction in the number of melanocytes, leading to the appearance of white patches, which are typically round and well-defined. Several mechanisms may contribute to the loss of melanocytes, including metabolic abnormalities, oxidative stress, cellular detachment, inflammation, autoimmunity, and more. The exact contribution of each of these factors is not yet clear, but it appears that an intrinsic defect in the melanocytes may be the initial event, and that an inability to adapt to oxidative stress in the melanocytes leads to a local inflammatory response and the activation of innate immunity. This skin decolouration mechanism is specific to vitiligo and varies among different types of leukoderma.
Key point to remember : All cases of vitiligo are instances of leucoderma, but not all cases of leucoderma are vitiligo.
Sources
BAHADORAN P. & LIPSKER D. Leucodermies. EMC - Dermatologie - Cosmétologie (2005).
BORRADORI L. & al. Dermatologie et infections sexuellement transmissibles. Elsevier Masson (2017).
EZZEDINE K. & al. Vitiligo: A Review. Dermatology (2020).
MEHTA M. What is Leukoderma? Know More About Its Causes, Symptoms, And Treatment. Dermatology (2022).
ABDELHADI S. & al. Chemical Leukoderma or Vitiligo – Where Do We Draw the Line? A Case Report. Case Reports in Dermatology (2024).
