This is a cyst of the vulva, a different anatomical location than the natal cleft where a pilonidal sinus occurs.
Perianal Crohn's disease can cause sinus tracts, but it is often associated with other signs like "knife-cut" fissures and underlying gastrointestinal disease.
An epidermoid cyst can occur in the sacral region, but a pilonidal sinus is a specific condition related to hair penetrating the skin, often with a visible sinus tract opening.
Folliculitis is a superficial infection of hair follicles, not a deep sinus tract or abscess like a pilonidal cyst.
While causing sinus tracts, HS typically affects the axillae and groin, not the midline natal cleft, and involves multiple, recurrent lesions.
