Malassezia species may play potential roles in the pathogenesis of meibomian gland dysfunction

Meibomian gland dysfunction (MGD) is the most common cause of dry eye disease (DED). Although many factors, such as aging, androgen deficiency, bacterial colonization and drug toxicity have been demonstrated to be associated with MGD, its pathogenesis is not well understood and definite therapies are lacking. Meibomian gland is the largest lipid-secreting gland of human and is the counterpart of sebaceous gland in the eyelid. The lipophilic yeast Malassezia species (spp) habitats in sebaceous gland and is generally considered to play pathogenic roles in seborrheic dermatitis. Several mechanisms have been illuminated, including secretion of lipases, production of toxic metabolites and generation of reactive oxidative species. Anti-fungal therapy is beneficial for patients with seborrheic dermatitis. So far, no previous studies have investigated the link between Malassezia spp and MGD. But there are reports which demonstrate increased prevalence of both high delivery and obstructive MGD in patients with seborrheic dermatitis. Malassezia spp is also found to be associated with anterior blepharitis, the seborrheic inflammation of the other counterpart of sebaceous gland in the eyelid-the Zeis gland. Based on the pathogenic role of Malassezia spp and its highly lipophilic characteristic, we hypothesize that Malassezia spp may also habitat in meibomian gland and play potential pathogenic roles in MGD. Anti-fungal treatment with 2% ketoconazole cream may be potential therapy for patients with MGD. If the hypothesis can be confirmed on patients, it can provide a novel insight of the pathogenesis of MGD and hopefully trigger further investigation into the relationship between microbiota colonization and the function of meibomian gland.