Table 2.

Clinical, dermoscopic and histopathological features of SFS.

	Clinical Features	Dermoscopy	Histopathology
Dermatophytes	Follicular micropapule.	Comma, broken and corkscrew hair, black dots and pustules with or without trapped hair.	Superficial and deep mixed perifollicular infiltrate. Positive PAS staining.
Candida	From small pustules to painful papules, nodules and pustules with the presence of itching.	Multiple whitish pinpoint pustules, scattered throughout the scalp. Peripheral erythematous halo with small dilated capillaries.	Dense perifollicular mixed-type infiltrate, edema, abscesses at the follicular epithelium and PAS-positive staining.
Malassezia	Folliculitis with small whitish scales on the scalp, erythematous-desquamative plaques with greasy appearance and seborrhea with greasy and opaque hair.	Furfuraceous scales, arborized vascular and atypical reticular dilatations, small whitish folliculitis, centered by the hair and a small crust secondary to itching.	Mild to moderate lymphocytic inflammatory infiltrate at the infundibular, peri-infundibular and peri-isthmic level, mild fibroplasia, abscesses, dilation of the infundibulum with laminated orthokeratosis and focal parakeratosis of the epidermis.
Bacteria	A single lesion with a tuft of hair. Yellowish-whitish pustule with perifollicular erythema, yellow-brownish crusts, painful perifollicular papular lesions with peripheral erythema.	A crusty thickened exudative lesion, yellowish in color, with a central tuft and peripheral erythema; brownish yellow background with an aflegmasic alopecia, atrophy, and absence of follicular openings.	Collection of neutrophils and bacteria in the epidermis with dilated vessels, edema, and mild-moderate mixed type -infiltrate in the papillary and middle dermis.
Herpes Zoster	Multiple vesicles and subsequent pustules following the innervation, with neuritis of the scalp.	Herpetic polymorphism: vesicles, pustules and crusts at the same time and peripheral erythema with numerous dilated and superficial capillaries, scabs and scarring lesions.	Intraepidermal vesicles containing multinucleated keratinocytes with a nucleus of grayish color, marginal chromatin, ballooning cytoplasm and acantholysis. A moderate-dense perivascular and interstitial inflammatory infiltrate of mixed-type fibrosis and destruction of the adnexal structures.
Pox virus	Hemispherical and roundish papules, in pale-pink color, 2–3 mm in diameter, with a central navel and a smooth regular surface.	Central umbilicated papule surrounded by yellowish-white polylobed amorphous structures. Crown vessels known as “red corona” emerge from the periphery of the lesion and radiate towards the center, rarely crossing each other.	Rounded basophilic bodies present among the keratinocytes are observed, grouped in a “crater” and in the infundibular hyperplastic areas of the granular and spinous layer of the epidermis.
Acneiform Eruption	Papules, pustules or follicular crusts on erythematous skin, pain with possible bleeding or leakage of pus.	Central pustular lesions, intensely erythematous with dilated capillaries in the periphery, crusts of variable colors from intense red to yellowish-brown, dilated vessels with a lattice appearance throughout the scalp.	Suppurative folliculitis in the superficial dermis with a neutrophilic inflammatory infiltrate, dilated sebaceous glands and hyperkeratinization of the intrainfundibular epithelium and retention of lamellae, plugs.
Rosacea	Diffuse erythema of the scalp with small dry scales, painful flat erythematous round lesions, and facial involvement.	Branching vessels with a yellowish central area that turns brownish over time.	Vasodilation of the vessels of the subpapillary plexus and a polymorphic inflammatory infiltrate, non-caseous granulomatous infiltrate in the perifollicular and perivascular areas, and the presence of Demodex Folliculorum.
Ofuji syndrome	Plaque of small erythematous-edematous, sterile pustules in seborrheic areas.	Central folliculitis with dilated capillaries in the periphery and yellowish crust.	Massive mixed-type inflammatory infiltrates, microabscesses, epithelial necrosis and intercellular edema.