Prurigo pigmentosa is a rare skin condition of unknown cause, characterized by the sudden onset of erythematous papules that leave a reticulated hyperpigmentation when they heal.

[1]: 57  The condition has been associated with a strict ketogenic diet in case reports in the medical literature.

[2][3] It was first reported by Masaharu Nagashima in 1978.

[4] Research has shown that it may be caused by gut bacteria dysbiosis as a result of ketosis.

[5] [6] This cutaneous condition article is a stub.