Differences between intrafollicular microorganism profiles in perioral and seborrhoeic dermatitis

Area of Science:

• Dermatology
• Microbiology

Background:

• Perioral dermatitis is often linked to topical corticosteroid overuse.
• However, it rarely develops in patients with seborrhoeic dermatitis despite long-term corticosteroid use.
• This suggests differing underlying causes for these conditions.

Purpose of the Study:

• To compare the intrafollicular microbial profiles in perioral dermatitis and seborrhoeic dermatitis lesions.
• To investigate the role of specific microorganisms in the pathogenesis of perioral dermatitis.

Main Methods:

• Tape-stripped samples were collected from lesions of perioral dermatitis (8), seborrhoeic dermatitis (10), and normal perioral skin (31).
• Microorganisms on plucked hair roots were evaluated microscopically after Toluidine blue staining.

Main Results:

• Fusiform bacteria (fusobacteria) were found on 20-70% of hairs in perioral dermatitis patients and some normal subjects.
• Malassezia yeasts were rarely observed in perioral dermatitis cases.
• Seborrhoeic dermatitis showed inverse results, with a higher prevalence of Malassezia and lower prevalence of fusiform bacteria.

Conclusions:

• Perioral dermatitis may be associated with conditions rich in fusiform bacteria.
• Seborrhoeic dermatitis appears to be linked to Malassezia-rich conditions.
• These findings suggest distinct microbial etiologies for perioral and seborrhoeic dermatitis.