Skin Elastic Recovery and Extensibility

Racial differences in skin elastic recovery (Table 5) and extensibility (Table 6) were recorded by Berardesca et al. (6) and Warrier et al. (10). Extensibility is measured by applying torque parallel to the skin and measuring the amount of stretch; elastic recovery is the time the skin takes to return to its original state after the torque is released.

These data vary by anatomic site of testing and by race, and age of study participants may affect the results, as well. Therefore, conclusions cannot be drawn from these data and further investigation, involving larger populations of participants and controlling for age differences, is necessary.

Table 4

Blood Vessel Reactivity







Topically administered MN

Blacks (6) (age 20 to 30); whites

Volar forearm

Vasodilator given:

(vasodilator); LDV and PPG

(6) (age 20 to 30); whites (6) (age 63 to 80)

• No significant difference in time to peak response, area under response-time curve, or time for response to decay to 75% of its maximum value

• PPG maximum response young black (40% less) < young white (P < 0.05)


Topically administered SLS

Black men (10) (age 29.9 ± 7.2);


SLS stress:

(irritant); LDV

white men (9) (age 30.6 ± 8.8)

• No significant difference between blacks and whites

• Blood vessel reactivity minimal in blacks from baseline to application of 0.5% SLS on untreated skin (see text for details)


Topically administered SLS

Hispanic men (7) (age

Upper back

SLS stress:

(irritant); LDV

27.8 ± 4.5); white men (9) (age 30.6 ± 8.8);

• Similar LDV response in Hispanics and whites

Table 4 Blood Vessel Reactivity (Continued)

References Technique Subjects

(18) Topically administered Black men (6);

corticoida (vasoconstrictor); Caucasian men (8)

(19) Topically administered MN Blacks (5); Caucasians (5);



Forearm After vasoconstrictor given:

• 40% decreased area under the curve response blacks compared to whites (P < 0.04)

• 50% decreased peak response in blacks compared to whites

• Decreased decay slope after peak blood flow in blacks compared to Caucasians; in blacks, y = 3.3672 - 0.0737x before treatment compared to y = 2.5347 - 0.0367 x after treatment (P < 0.04) => i.e., less blood vessel reactivity in blacks

Upper 1/3 volar Vasodilator given:

forearm • Area under the curve for LDV

response versus time blacks > Caucasians for all MN concentrations (P < 0.05)

• Area under the curve for LDV response versus time

Asians > Caucasians for higher dose levels of MN (P < 0.05)

(7) Topically administered MN Blacks (7); Caucasians (8); Volar forearm Vasodilator given:

(vasodilator); LDV Asians (6) (ages 23 to 32) • Before tape stripping: no difference between the groups in basal perfusion flow, but lag time before vasodilatation was blacks > Caucasians > Asians (P < 0.05)

• After 8 and 12 tape strips: lag time before vasodilatation decreased in all three groups, but significantly decreased in Asians > Caucasians > blacks (P < 0.05)

aCorticoid, clobetasol propionate 0.05% ointment.

Abbreviations: MN, methyl nicotinate; LDV, laser Doppler velocimetry; PPG, photoplethysinography; SLS, sodium lauryl sulfate.

Source: Adapted from Ref. 2.

Table 5 Skin Elastic Recovery

Reference Technique

In vivo

ie Subjects



Blacks (15)

Volar and

• No significant

(mean age


difference between

46.7 + 2.4);


races on dorsal forearm

whites (12)

• Elastic recovery blacks

(mean age

(26% less) <

49.8 + 2);

whites on volar

Hispanics (12)

forearm (P < 0.001)

(mean age

48.8 + 2)

Black women

Left and right

• No significant

(30); white

medial cheeks,

difference between

women (30)


races on the legs

(ages 18 to 45)


• Elastic recovery blacks


1.5 x > whites


on cheeks (P < 0.05)


In vivo

In vivo

Source: Adapted from Ref. 2.

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