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Chances and Limitations
of Predicting the Skin Type by Using Colormetric Data
Kleinschmidt, Juergen1,
Radl, Bernd1 and Kleinschmidt, Stefan1
Institute of Medical Balneology and Climatology at Ludwig-Maximilians-University
of Munich1
Abstract-
Objective: The skin type is used in tanning industry, in epidemiology
(e.g. concerning skin cancer), in standardisation rules, in UV-therapy,
etc. Never-the-less there is no objective equipment to validate the
subjective explorative answers to the FITZPATRICK-questionaire, concerning
the retrospective usual reaction of the skin to the annual first solar
UVR-exposition. To obtain objective criterias we tested methods of combining
different colorimetric parameters in order to estimate the skin type
prospectively. Design: 164 dermatologic patient, who were treated
4 weeks in a German dermatological SPA-clinic (TOMESA-Clinics Bad Salzschlirf),
were classified a) by different health professionals (clinical dermatololgical
experts) and b) by 1 medical student, based on literature-standards.
In this way we obtained almost 100 patients with 4 unquestionable FITZPATRICK-skin-types.
The others belong to overlapping classes of skin types. Independently
from subjective classification, the skin color of the patients was measured
without skin contact by a colorimetric apperatus (ER50, JOHNE & RAILHOFER
Co, Munich) at the forearms (ventral and lateral, left and right) and
in the gluteal region (left and right). By means of 1) discriminance
analysis 2) hierachical calculation models 3) cluster analysis of the
colorimetric data one can calculate the skin type, based on the unquestionable
skin classes. To evaluate the concordances between subjective skin type
classifications and the overlapping classes we definde summarized definitions
for sensitivity and specifity. Results: Between predicting the
skin type by chance (sensitivity = 25 %) and the ideal endpoint (100
%) we reached more than 65 % sensitivity, depending on the calculation
model. This is quite high, compared to experts prediction and an experimental
evaluation by LEHMANN, who used WUCHERPFENNIG-Erythem-Treppe at 113
dermatologic patients (27 %). The stepwise cluster analysis suggests
to use just 3 Skin Type Categories oder at least 7 (or more). Conclusions:
We suggest to define theoretical Skin Types, based on colorimetric data,
to be used in standardisation efforts. The evidence of our method is
just as good or bad as the theoretical CIE-definition SED compared to
the individiual MED.
Keywords: skin
type, colorimetric data, CIE standardisation, UVR sensitivity
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