The prevalence of melanoma or skin cancer is seen mostly in people who have white skin. Melanoma occurs less frequently among blacks, Asians, Central and South American populations. The reason for this can be attributed to the fact that the latter group is better protected against the environment due to their skin pigmentation and possibly their exposure to the sun is different and done wisely.

In the United States, for every one black Afro American person with melanoma there are 17 Caucasians suffering from this disease. However, it must always be kept in mind that people with pigmented skin can develop melanoma and are also at risk though the incidence is lower. Just as in white populations, dermatoscopy seems to be the best method in detecting melanomas in non-white populations as well.

The Risk areas

For people with dark skin, melanomas are found to occur in the relatively non-pigmented areas of the skin like the palms of the hands, soles of feet and under the nails. To dermatologists these types of melanomas are called the acral lentiginous type or subungual melanoma.

Delay in Diagnosis

Melanoma, though low in incidence among non-whites, have poorer prognoses compared to white skinned populations due to the increased chance of late diagnosis. This problem can be attributed to the fact that in non white populations, pigmented skin lesions are rarely noticed and are difficult to detect by clinical examination. This results in delayed initiation of treatment compared to whites where these lesions are more easily noticeable. So reduced visibility of melanocytic lesions leads to delay in seeking medical help. This is further compounded when examination by physicians using the naked eye results in misdiagnosis or when the examination is not conducted properly. It has been shown that when diagnosed in the correct manner, at an early stage, prognosis of melanoma in non-white populations is comparable to that in case of white populations. Using a dermatoscope to examine dark skin for melanomas could help improve the chances of correct diagnosis and earlier treatment intervention

Dermatoscopy as essential in dark skin as in white

For non whites, poor prognosis due to delay in diagnosis makes it all the more vital that this population is made aware of this fact. In addition, dermatologists need to be skilled in differentiating melanocytic lesions from physiological pigmentation and should be well versed in the use of superior detection instruments. While in whites, naked eye examination alone is insufficient in detecting problem areas, in dark skinned individuals this becomes a double jeopardy.

It is therefore imperative that physical examination is more effectively done by dermatologists for early detection and consequent successful immediate therapy. In this way the lower incidence of melanoma in non-whites should not stop dermatologists from making early diagnosis and accurately classifying pigmented lesions.

In the last decade, the use of Dermatoscopy in clinical dermatological practice has played an important role in improving diagnostic accuracy. Lesions appearing suspicious by eye examination can be grouped correctly, thereby reducing misdiagnosis by clinical examination resulting in the incidence of unnecessary excisions for biopsies.

Proven Superiority of Dermatoscopy Over Other Methods

In whites, it has been proved that dermatoscopy is able to improve diagnostic results in examination of pigmented lesions and this has encouraged dermatologists to progressively adopt this technique over clinical examination based solely on the naked eye examination method. Studies have also confirmed that the use of dermatoscopy in the detection of pigmented lesions in non-whites and blacks can lead to early and accurate diagnosis of melanoma.

It has been confirmed through experiments that there is a 97% success rate in detection of lesions accurately in people with dark skin with the use of Dermatoscopy. There is a high level of interobserver agreement for the dermoscopic variables like pigmented lesions, streaks, globules, blue-whitish veils, and milia like cysts.

Clark nevi were easily diagnosed by the use of dermatoscopy in this group by a network of pigment and presence of globules. Benign melanocytic lesions were also detected as were sebhorric keratoses, which were characterized by presence of milia like cysts. Blue naevi revealed bluish pigmentation. The melanomas in dark skinned people were confirmed by the presence of bluish white veils, irregular globules and streaks at the edges in the same manner that it is confirmed in cases of melanoma in white skinned people.

So, dark skin does not impede the identification of any dermoscopic feature. Naked eye examination on the other hand poses a problem of misdiagnosis. However, in some dark skinned people, a stronger source of light is used with the dermatoscope, as dark skin tends to absorb a large amount of light rays. The newer dermoscopes improve vision due to excellent light emitting diode illumination.

Just as in case of the caucasian population, demoscopy is equally effective and superior as a method of melanoma detection in the dark skin populations as well. It plays a more vital role in this group as only by this method is it possible to detect melanocytic lesions accurately and timely enabling early therapy, reduction in the number of unnecessary excisions, reduction in scarring, and lowering social costs.