Granular Parakeratosis of the Eccrine Ostium: A Case Report.

Granular parakeratosis (GP) is a unique keratotic disorder that often affects the intertriginous areas. GP usually presents as erythematous or brownish hyperkeratotic papules or plaques and can be further classified into five types. GP of the eccrine ostium is a rare subtype; its pathological defects are mainly localized to the stratum corneum of the eccrine ostia. Due to its rarity, there is usually a delay in diagnosing GP, and these patients are often misdiagnosed with other dermatological conditions. In this report, we present the case of a 64-year-old Thai female who presented with recurrent pruritic erythematous rashes on her neck since approximately 40 years. She was previously diagnosed with eczema or folliculitis. Histopathological examination confirmed a final diagnosis of GP of the eccrine ostium. She was advised to avoid excessive heat and keep her intertriginous areas dry. Her condition improved significantly during the follow-up visit.