A prostaglandind-synthase-positive mast cell gradient characterizes scalp patterning

Abstract

Pattern (androgenetic) alopecia is commonly encountered in scalp biopsies obtained for non-scarring hair loss. Prostaglandin D-synthase is known to be elevated in bald vs. non-alopetic scalp of patients with androgenetic alopecia. We hypothesized that this difference in pattern of prostaglandin D-synthase expression may constitute a developmental pattern inherent to normal as well as alopecic scalp skin, thus defining a 'field' vulnerable to acquired hair loss. We immunohistochemically mapped prostaglandin D-synthase expression from supra-auricular to vertex scalp skin of 11 cadavers. We found significantly more dermal mast cells immunoreactive for prostaglandin D-synthase in the vertex compared to the lateral aspects of the scalp, with a decrement that spatially approximated the pattern of androgenetic alopecia. This difference was present in both balding and non-balding scalps and was independent of gender. Dual labeling established dermal cells expressing prostaglandin D-synthase as mast cells. These data indicate that scalp is spatially programmed via mast cell prostaglandin D-synthase distribution in a manner reminiscent of the pattern seen in androgenetic alopecia.