Foxtail millet papule (milium) can be divided into primary and secondary types. The former is formed by the epithelium at the lower end of the vellus hair fistula, while the latter occurs secondary to subepidermal bullous diseases such as bullous pemphigoid, dystrophic epidermolysis bullosa, and porphyria cutanea tarda, as well as retention cysts caused by epithelial or skin appendage hyperplasia following grade II burns or dermabrasion.

bubble_chart Pathological Changes

Similar to epidermal cysts, differing only in size. The cyst wall is composed of stratified squamous epithelial cells, and the cyst cavity is filled with concentric layers of keratin. In serial sections, the primary foxtail millet papule can still be seen connected to the vellus hair follicle by an epithelial stalk. Secondary foxtail millet papules may be connected to hair follicles, sweat gland ducts, sebaceous gland ducts, or the epidermis.

bubble_chart Clinical Manifestations

It appears as a yellowish-white, firm, spherical papule with a smooth surface, measuring 1–2 mm in diameter, covered by an extremely thin epidermis, from which a firm keratinous ball can be extruded. Primary lesions commonly occur on the face, particularly around the eyelids. Secondary lesions develop on the surface and periphery of pre-existing rashes. The lesions progress slowly, may persist for many years, and eventually shed and disappear naturally. There are usually no subjective symptoms.

bubble_chart Treatment Measures

After local disinfection, use a needle to puncture the epidermis and remove the yellowish-white granules, or perform grade I electrodessication with a fine needle.