Inflammation

The microcomedo will continue to expand with densely packed keratin, sebum, and bacteria. Eventually this distension will cause follicular wall rupture. The extrusion of the keratin, sebum, and bacteria into the dermis results in a brisk inflammatory response. The predominant cell type within 24 hours of comedo rupture is the lymphocyte. CD4 + lymphocytes are found around the pilosebaceous unit while CD8+ cells are found perivascularly. One to two days after comedo rupture, the neutrophil becomes the predominant cell type surrounding the burst microcomedo (26).