Any guesses as to the cause/diagnosis? By tomorrow if no one gets the right answer I'll edit this post and tell what it is, so be sure to check back!!!🚑🚑 *EDIT* Tunga penetrans (chigoe flea or jigger) is the parasitic insect responsible for these marks. It's the smallest known flea (1 mm in length) here we see it embedded under the stratum corneum layer of the skin.