No apparent change is observable by the eye for several days; indeed, not till the fourth, in many cases, is there any evidence of a vesicle; about the fifth day, however, a pink areola, or circle, is observed round one or all of the places, surrounding a small pearly vesicle or bladder.
"The Book of Household Management"
Mrs. Isabella Beeton
By the tenth day it has the appearance of a pustule about the size of a ten-cent piece, surrounded by a red areola about three inches in diameter.
"The Mother and Her Child"
William S. Sadler Lena K. Sadler
The shade that the areola assumes will vary according to the complexion of the individual, growing darker in brunettes than in blondes.
"The Prospective Mother A Handbook for Women During Pregnancy"
J. Morris Slemons