The Role of the Skin Microbiota in Acne Pathophysiology

S. Ramasamy; E. Barnard; T.L. Dawson Jr; H. Li


The British Journal of Dermatology. 2019;181(4):691-699. 

In This Article

Acne and Fungi

Modern microbiology techniques usually report populations of Cutibacterium spp., Staphylococcus spp. and Malassezia spp. in follicular contents.[61] It is likely that bacteria are not the only important factor in acne pathogenesis; fungal species such as Malassezia have also been hypothesized to play an important role.[61,62] Currently, a clinical diagnosis of acne often represents a spectrum of disorders of differing aetiology. Differential diagnosis of the type of acne requires careful consideration, as there are subtle but real differences in the clinical presentation of fungal folliculitis vs. normal acne.[62,63] Folliculitis caused by fungal infection appears as small red bumps or closed comedones, which may be clinically confused with acne. Fungal microorganisms usually do not cause facial acne unless they grow in large numbers deep inside pores, where they are usually not found at all. If these fungi grow inside a pore, they must have an abnormal source of oxygen. The fungus that causes the acne-like bumps (Pityrosporum folliculitis) is likely to be Malassezia.[43,64] When present, Malassezia break down useful fatty acids into other chemical structures that are known skin irritants, and secrete proteins and peptides that are known allergens.[65] The specific disease mechanism caused by fungi, and even their presence and number in disease skin vs. healthy skin, remains to be sufficiently investigated.