Phototype comparison between caucasian and asian skin types

Received on: 13/09/2011
Approved on: 22/09/2011

This study was carried out at the Hospital de
Clínicas da Universidade Federal do Paraná
(HC-UFPR) – Curtiba (PR), Brazil.

Conflicts of interests: none
Financial support: none

Abstract

Introduction: Evaluating the response of various skin types to ultraviolet radiation expo- sure is very important in dermatology. The Fitzpatrick system is the most frequently used classification technique. It is straightforward and practical, assesses photodamage and skin cancer risks, and helps in defining light-based treatments. Nevertheless, there seem to be limitations to its use in non-Caucasians.
Objective: To compare the subjective phototype evaluation method to the Fitzpatrick classification in Caucasian and Asian (East and Southeast Asian, in particular) skin types.
Methods: Caucasian and Asian women (n = 42) were classified using 3 evaluation meth- ods (clinical, Fitzpatrick and Modified Fitzpatrick). The data were collected through ques- tionnaires and analyzed using non-parametric methods. A 5% significance level was adopted.
Results: There were no statistically significant differences within each group between the clinical evaluation, Fitzpatrick classification and the Modified Fitzpatrick classification (Caucasian cr2 = 0.375, p = 0.93 and Asians cr2 = 3.5, p = 0.182).
Conclusion: The three methods evaluate phototypes equally, yet studies with larger pop- ulation samples are still necessary.

Keywords: SKIN, SKIN PIGMENTATION, PHOTOBIOLOGY

INTRODUCTION

Many patients of Asian descent seek dermatological care. Knowledge about the skin type, anatomy, physiology and unique aspects of Asian ethnicities allows for better decision making and treatment planning for these patients.

The Fitzpatrick classification is widely used to determine a patient''''''''s skin type. While Asian patients are usually considered to be phototypes IV and V, that classification has been questioned by some authors. 1,2 Therefore this study compares the subjective assessment of phototypes using the Fitzpatrick classification in Caucasian and Asian patients.

METHODS

This study consisted of a transversal analysis carried out through data collection and interviews. All methodological cri- teria complied with the current terms and rules for research in human beings – Resolution 196/96 of the Brazilian National Health Council and the most recent version of the Declaration of Helsinki. The study was also approved by the Research in Human Beings Ethics Committee of the hospital where it was carried out.

Caucasian women were recruited at the dermatology out- patient clinic of the hospital where the study took place, and Asian women (of Japanese, Chinese or Korean descent) were randomly recruited at an Asian community event in Curitiba (SP, Brazil). All study participants were classified using three assessment methods (clinical, Fitzpatrick classification and Modified Fitzpatrick classification).

All participants answered a questionnaire about maternal descent, paternal descent, their personal features (eye color, nat- ural hair color, color of the skin in areas without exposure to the sun, presence of freckles in exposed areas, skin sensitivity to the sun and degree of tan grade). A dermatologist physician from the study hospital and a medical scholar evaluated patients'''''''' pho- totypes using the subjective classification method. The photo- types were also classified according to the Fitzpatrick (Table 1) and Modified Fitzpatrick (Table 2) classifications based on the data supplied in the questionnaires, which were answered with- out the researchers'''''''' involvement.

The data collected from the questionnaires were input into an Excel spreadsheet and analyzed using the Friedman test. A 5% significance level was adopted.

RESULTS

Female patients (n = 48, 18 Asian and 30 non-Asian) were analyzed. Of the Asian patients, 15 had both maternal and pater- nal Japanese ancestry, and three had paternal Japanese ancestry only. The average age was 29 (range 22-38). In the non-Asian group, patients'''''''' ancestry varied between French, German, Italian, Brazilian native Indians, Polish and Portuguese, with an average age of 36 (range 22-63).

There was no significant statistical difference within each group between the medical evaluation and the Fitzpatrick and Modified Fitzpatrick classifications when analyzed using the Friedman test. Caucasian cr 2 = 0.375, p = 0.93 (Table 3 and Figure 1) and Asian cr 2 = 3.5, p = 0.182 (Table 4 and Figure 2).

DISCUSSION

Few studies on the dermatological implications of ethnic differences have been published in the indexed literature. Most published papers compare Caucasian and black populations. Although Asians constitute a huge portion of the world''''''''s popu- lation, studies about Asian individuals are rare except in medical journals published in Asia.

Since Brazil has one of the largest Asian-descended popu- lations in the world, there is a significant number of medical consultations with that population. Moreover, with migration and intermarriage, it is increasingly common to find traces of several races in the same individual. For that reason – not only in dermatology but also in other medical specialties – a broad understanding of each ethnic group''''''''s unique aspects is important to improve patient treatment.

Evaluating the skin''''''''s response to ultraviolet radiation expo- sure is very important in dermatology, especially in photoder- matosis, phototherapy, photoaging, photocarcinogenesis and photoprotection. It is also very useful when planning procedures such as surgery, laser therapy, peelings and dermabrasion. Classifying the skin by phototype is the most frequently used method because it is simple, straightforward and practical.

The classification of skin phototypes developed by Fitzpatrick in 1975 assesses the skin''''''''s sensitivity to ultraviolet radiation, in the context of an individual''''''''s tendency to burn or tan. It is a subjective evaluation based on answers to patient- administered questionnaires. Classifying the skin into six types allows an assessment of the risks of photodamage and skin can- cer, and helps plan phototherapy treatments by estimating the correct UV dose to minimize erythema and define the param- eters of light-based treatments. 2-4

The phototype category might not be the most effective evaluation of photosensitivity; this can be better estimated by determining the minimum dose of UV radiation that causes erythema, according to Wee and colleagues 2 , who also suggest that genetics and environmental influence can affect that deter- mination. Studies by Satoh and Kawada showed different responses from Japanese and Caucasian skin to ultraviolet radia- tion, and proposed the Japanese Skin Type assessment method. 1,4,5 Other authors demonstrated that UVB radiation is more erythemogenic than melanogenic in mongoloids. 6

Although no statistical difference was observed among the three methods, the phototypes of Asian patients ranged from II to V, according to the assessment method used in this study. It was also verified that the physician''''''''s subjective evaluation can diverge from the questionnaires on the skin''''''''s reaction to sun exposure. In the Caucasian population, the medical evaluations correlated more closely with the other methods.

CONCLUSION

In light of these results, a more detailed individual analysis should be made of Asian skin characteristics and reaction to ultraviolet exposure, when in preparation for aesthetic proce- dures and phototherapy. More studies and a larger sample pop- ulation are necessary to more broadly confirm those results.

References

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2 . Wee LKS, Chong TK, Koh Soo Quee D. Assessment of skin types, skin colours and cutaneous responses to ultraviolet radiation in an Asian population. Photodermatol Photoimmunol Photomed. 1997;13 (5-6):169-72.

3 . Sachdeva S. Fitzpatrick skin typing: Applications in dermatology. Indian J Dermatol Venereol Leprol. 2009; 75(1):93-6.

4 . Roberts WE. Skin type classification systems old and new. Dermatol Clin. 2009; 27(4):529-33.

5 . Kawada A, Noda T, Hiruma M, Ishibashi A, Arai S. The relationship of Sun protection factor to minimal erytema dose, japanese skin type, and skin color. J Dermatol. 1993; 20(8):514-16.

6 . Kawada A. Risk and preventive factors for skin phototype. J Dermatol Sci. 2000; 23(Supll 1):27-9.