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Vitiligo, sun and skin cancer

 A commentary by Professor KU Schallreuter MD

Clinical Director of the Institute for Pigmentary Disorders in association with E.M. Arndt Universiy of Greifswald/Germany and University of Bradford/UK


This is a response to the special feature article in Dispatches 40 / October 2005 of the UK Vitiligo Society and to a recent article in “The Times” T2 Body and Soul section about the skin cancer risk in patients suffering from vitiligo.

What is vitiligo?

This seems a redundant question.

However, it seems important to recognise that vitiligo is a disease according to the World Health Organisation.

Vitiligo is neither a condition nor a symptom.

The characteristics of this disease are the acquired sudden loss of the inherited skin colour. Despite its long recognition, the cause of this disease is still unknown.

The loss of the skin colour yields white patches of various sizes which can be localised anywhere on the body. The disease affects all races, men and women and all age groups. Approximately 1 in 200 of the world population develops vitiligo.

The affected individual shows often severe disfigurement, particularly when the face and the hands are involved.

However, not all white skin patches are vitiligo. There are other conditions and diseases which are associated with white skin. A long time ago the term leucoderma has been introduced. This word originates from the Greek language and means white skin. Clearly it seems mandatory to make the correct diagnose. This can be done by Wood’s light. Vitiligo shows a very characteristic fluorescence under this condition which is absent in other leucodermas (Schallreuter et al, Science (1994))


Sutton Nevus (Halo-Nevus) is not vitiligo

Leukodermas of other origin are for example the Sutton Nevus also called Halo-Nevus. Despite both vitiligo and Sutton nevus can occur together at the skin of the same individual, it has been shown that these are two very different diseases (Schallreuter KU et al Arch Dermatol Res (2004))

Future work needs to show why both vitiligo and Halo-Nevi frequently occur together.


Skin colour and sun protection

For decades it was believed that skin colour with its pigment (melanin) content fosters sun protection. However, the sun protection factor (SPF) is only between 2-3 for the brown / black melanin (eumelanin), while the red pheomelanin hardly protects at all, it is even photoactive and generates reactive oxygen species (ROS) (Chedeckel MR and Zeise L, Lipids (1998, Johnson BE et al Nat New Biol (1972)). It is becoming evident that besides melanin formation many other mechanisms and factors are in place to defend the human body against environmental reactive oxygen species (ROS) formation (Schallreuter KU and Wood JM Photobiology (2001)). ROS can also be generated by ultraviolet light directly inducing a plethora of signalling and defence mechanisms.

In vitiligo patches the pigment is mostly completely absent, but not all individuals suffer from sun burn despite sun exposure (Schallreuter KU et al, Dermatology (2002)).

Moreover, it has been documented at least in 2 major studies that vitiligo per se does not necessarily coincide with increased sun sensitivity (Calanchini-Postizzi E and Frenk E Dermatologica ( 1987); Schallreuter KU et al (2002))


Skin ageing and vitiligo

Interestingly, the skin of vitiligo sufferers does not age with the same speed compared to age and sex matched healthy people who do not have vitiligo (Schallreuter KU et al (2002)). The results stem from a clinical study of patients with vitiligo who did not avoid sun exposure completely. Hence, it would be of great value to understand this phenomenon. This observation clearly indicates that some other protective mechanisms must be in place to yield this result.

However, it is also beyond any doubt that excessive sun exposure over time can induce non melanoma skin cancer (NMSC) in general in susceptible individuals.

The development depends on the genetic background and on the accumulation of sun exposure times / sunburns over time.

In this context it is noteworthy that fair skin people who always burn and never tan are much more prone to develop skin cancer compared to good tanners and dark skin coloured individuals. But there are also exceptions. Even dark skin people can occasionally be very sun sensitive.


Vitiligo and skin cancer

The result of two major studies showed that patients with vitiligo do not have a higher risk to develop sun induced skin cancer (Calanchini-Postizzi E and Frenk E (1987) , Schallreuter KU et al (2002)).

In the recent past an issue was put forward that PUVA therapy which is a frequently used treatment modality for vitiligo could be of potential risk to enhance the risk of skin cancer and their precursors (actinic keratosis) in these patients (Halder RM et al Arch Dermatol(1995)). Considering the amount of rays which these individuals receive, it seemed reasonable to question the possible side effects. However, until now there is no documentation in the literature about a true coincidence. (Westerhof W and Schallreuter KU Clin Exp Dermatol (1997)). A recent publication by Grimes states that there is also no enhanced risk after the use of narrowband UVB exposure which is a treatment modality utilised as mono therapy with increasing doses 2-3x per week in adults and even in children (Grimes P, JAMA ( 2005)).


Vitiligo and melanoma

Malignant Melanoma (MM) is another skin cancer which can be very dangerous if not recognised early. There are many reports linking this malignancy with altitudes and excessive periodic sun exposure. 

People with very fair skin (those who never tan or only very slightly) do have a higher risk to develop melanoma compared to dark skin people at any body site regardless of sun exposure or not. These tumours can develop in existing moles but they can also arise totally new as pigmented as well as non-pigmented tumours. Early recognition and excision are important for the outcome.

The observation that melanoma is more frequent in patients with vitiligo originates from a study which included 623 Caucasian patients with melanoma of the Oncology Clinic at the Department of Dermatology at the University of Hamburg/Germany (Schallreuter KU et al, Dermatologica (1991)).

In this study 11/623 patients with melanoma had a true vitiligo long before their melanoma was diagnosed. Considering that 1 in 200 has vitiligo and 1 in 12,000 develops melanoma, these results suggested a significantly higher risk to develop melanoma for patients with vitiligo and fair skin (Schallreuter KU et al, Dermatologica (1991)).

In our Institute for Pigmentary Disorders we have indeed found in 2 Caucasian patients with vitiligo melanoma in a patient group of 1800 Caucasian patients with vitiligo supporting the above findings (Schallreuter KU, unpublished results).

Based on the above results the take home message and recommendation is that patients who have vitiligo should undergo an annual total body examination at their Dermatologists in order to recognise a possible melanoma as early as possible.


Melanoma associated leucoderma

Some individuals with melanoma develop patches of white skin in the vicinity of their melanoma or after their tumour had been excised. In this context it seems important that these white patches are not vitiligo. This skin shows a very different molecular biology and biochemistry compared to true vitiligo (Kothari, S PhD Thesis U of Bradford 2005). Therefore the term melanoma associated leucoderma seems more appropriate as already suggested earlier by the late Fitzpatrick.


Are white skin patches associated with melanoma beneficial for the outcome ?

The development of white patches anywhere on the skin in association with melanoma was interpreted to be a beneficial sign in the outcome for survival time. There is still an ongoing debate whether the development of such leucoderma associated with melanoma is of true value for the individual’s outcome or not (Lerner AB, Nordlund JJ Arch Dermatol (1977); Nordlund JJ, Lerner AB Arch Dermatol (1979); Nordlund JJ et al J Am Acad Dermatol (1983)). This author feels that there is at the present time not enough evidence to support this statement. Larger patient groups are needed in order to conclude. Therefore, it is simply not correct to advise patients with vitiligo that they have a decreased risk to develop melanoma and that they are well protected against this tumour.