The cutaneous microflora of adolescent, persistent andlate‐onset acne patients does not differ

The cutaneous microbiology and antibody status to Propionibacterium acnes of patients with persistent (males, n = 32; females, n = 33) and late‐onset (females, n = 25) acne were compared with individuals with adolescent acne (males, n = 22; females, n = 18) and normal control volunteers (persistent acne: males, n = 26; females, n = 30; late‐onset: females, n = 20). Males had significantly higher grades of acne compared with females (P < 0·05). The microflora consisted in the main of propionibacteria, staphylococci and Malassezia; other bacteria represented less than 0·01% of the total microflora. At all sites for all samples there were significantly more propionibacteria than staphylococci or Malassezia (P < 0·05). There were significantly higher (P < 0·05) numbers of microorganisms in follicular casts from patients compared with their control volunteers for female facial skin and male back skin. Twenty‐six papules and 48 normal follicles were analysed. A bimodal distribution of microbial colonization was noted, with about 90% of normal follicles and about 10% of acne follicles having no detectable viable microorganisms. Anti‐P. acnes IgG antibody titres were measured using a secondary fluorescein isothiocyanate antibody technique, and no significant differences in titre were found between any groups of patients (P > 0·05). Correlation analysis showed no association between the population densities of P. acnes and anti‐P. acnes IgG titres. There were no differences in the microbiology of skin of adolescent acne patients, persistent acne patients or late‐onset acne patients which could account for these various forms of acne.