microcomedones

Microcomedones are the earliest, microscopic stage of comedone formation in acne vulgaris. They represent a initial dilation of the hair follicle’s infundibulum filled with keratin and sebum, occurring beneath the skin surface. Because they are not visible during routine examination, microcomedones are not diagnosed clinically and are primarily described in histological and research contexts as the precursor to visible comedones.

Pathophysiology involves altered keratinocyte turnover and desquamation within the follicular infundibulum, alongside increased sebum production. This combination promotes keratin plug formation that occludes the follicular opening. The plug can expand the follicle, creating the microscopic lesion that may later evolve into open (blackhead) or closed (whitehead) comedones and, subsequently, inflammatory acne.

Clinically, microcomedones help explain the progression from noninflammatory to inflammatory acne. They are typically not identifiable by eye or touch and are studied primarily through skin biopsies or imaging in research. Recognizing the concept supports the rationale for treatments aimed at normalizing follicular desquamation and reducing sebum.

Treatment implications focus on preventing progression by addressing keratinocyte turnover and sebum production. Topical retinoids are commonly used to normalize desquamation and prevent follicular plugging. Other agents, such as benzoyl peroxide and salicylic acid, provide comedolytic or antimicrobial effects and may be included in combination regimens to mitigate progression to visible lesions.