Is vitiligo a rare disease?

According to the World Health Organisation (WHO), a disease is classified as "rare" when it affects less than one person in 2,000, that is, when its prevalence is less than 0.05%.

Many people consider vitiligo to be a rare disease. However, it is more common than one might think. According to estimates from the WHO, vitiligo affects between 0.5 and 2% of the global population, equating to several tens of millions of people. This prevalence varies by region, with higher rates in certain populations. For instance, in India, some studies report a prevalence of 8.8% for vitiligo. In the United States and Europe, the figure generally hovers around 1%.

These data suggest that vitiligo cannot be categorised as a rare disease in the strictest sense of the term. Its frequency far exceeds the thresholds defined by health organisations, distinguishing it from other dermatoses considered as rare diseases, such as localised scleroderma or Cowden's syndrome. If vitiligo is sometimes perceived as a rare disease, it's due to its underrepresentation in the media and the general lack of knowledge about it. Several factors contribute to this impression:

• A variable clinical expression : Vitiligo does not manifest in the same way in all patients. Some present with large, highly visible depigmented patches, while others have only a few discreet spots. Similarly, some patients have a vitiligo that remains stable for years while others experience rapid progression. This variability can give the impression that the disease is less common than it actually is.

• A lack of awareness : Unlike other dermatological conditions, such as the acne, the eczema or the psoriasis, vitiligo is less frequently addressed in awareness campaigns, which can reinforce the notion that it is a rare disease.

• A social discomfort associated with vitiligo : Many individuals with vitiligo seek to conceal their white patches, using covering clothing or other means. This discretion is often due to fear of others' reactions and, in some cultures, a still strong stigmatisation of skin depigmentation. This phenomenon can create the impression that vitiligo is rare, when in fact it is simply hidden and not easily noticeable in daily life.

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