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Clinical Updates

Chee-Leok Goh

An Epidemiology of Acne Vulgaris in Singapore

Chee-Leok Goh

Friday, February 15, 2013


Acne vulgaris is a common skin disorder amongst adolescents. Reports on its prevalence in adolescents range from 30-100%1 and it has been reported to occur in up to 91% and 79% of male and female teenagers, respectively.2 In a randomized sample of 522 subjects aged 15-25 years in Hong Kong, 52% had acne,3 of which 27% were psychologically disturbed by the condition, but only 2% sought treatment from a doctor.

At the National Skin Centre in Singapore, acne is consistently among the top 10 conditions for which patients seek treatment.4,5 In 2011, there were 8,699 new cases of acne vulgaris seen at the National Skin Centre, a tertiary dermatology referral centre in Singapore. This accounts for about 11% of the total number of new cases seen in that year. Acne is the second most common skin disease after dermatitis/eczema.

In Singapore, a community-based cross-sectional study in 2007 of 1,045 adolescents aged 13-19 years showed that 88% identified themselves as having acne. Most acne occurred in the adolescents but a proportion of acne appeared in adulthood (Figure 1). Of the 806 who were examined by a dermatologist, 51% had mild acne, 40% moderate acne and 9% had severe acne (Figure 2). Twenty-eight percent had acne for less than 6 months, 18% for 6-12 months, 22% for 1-2 years, and 31% for more than 2 years. Eighteen percent reported a history of either parent having acne, while 25% reported having a sibling with acne. There were no statistically significant correlations between the severity of acne, race or gender and family history of acne. Only 32% had sought treatment from a doctor for their acne vulgaris.6

Figure 1. The prevalence of acne vulgaris patients seen at a tertiary dermatology referral centre in Singapore according to sex and age group in 2011


Figure 2. showing acne vulgaris of different severity (mild, moderate and severe)


Propionibacterium acnes resistance to antibiotics has been a concern for decades, since the introduction of oral antibiotics for the treatment of acne. Resistance rates have increased over the years, and antibiotics resistance in Singapore is no exception. In a study carried out in 1999, the antibiotic resistance rate was 11%.7 In that study, no resistant strains were identified in patients who had not received any antibiotics. In the 2007 study, antibiotic-resistant strains of P. acnes were detected in 26 out of 262 isolates (15%), of which, 11 of these 26 subjects (42%) had received or were receiving antibiotic treatment for acne. The other 58% of students who had antibiotic-resistant strains of P. acnes did not give a history of prior antibiotic therapy. In a preliminary report (unpublished) of a recent study carried out in Singapore, the resistant rate has increased to about 22%. When the mean minimum inhibitory concentrations (MICs) of sensitive strains were compared between antibiotic-naive patients and those with prior history of antibiotic treatment, the latter tended to have higher mean MICs. The report indicated that the most common resistance was to erythromycin, and all strains that were resistant to erythromycin were also resistant to clindamycin (Table 3).6,7 Long-term use of antibiotics by acne patients, compounded by poor compliance, promotes the development of resistant strains.

Table 1. Increasing antibiotic resistance of P. acnes in Singapore

Year % P. acnes resistant strains
1999 11%
2007 15%
2010 22%

Table 2. Antiobiotic-resistant isolates of P. acnes

Antiobiotic Number of subjects % of isolates % of resistant isolates Prior/present antibiotic history
Doxycycline 6 3.4 23 4
Tetracycline 3 1.7 11.5 3
Minocycline 3 1.7 11.5 3
Co-trimoxazole 10 5.7 38.5 3
Clindamycin 13 7.5 50 9
Erythromycin 18 10.3 69.2 11

Ref: H-H. Tan et al. Br J Dermatol 2007;157:547-551.

Table 3. Mean MICs of antibiotic-sensitive isolates of P. acnes

Antiobiotic Mean MIC - antibiotic-naive
subjects μg mL-1
Mean MIC - subjects with prior
antibiotic treatment, μg mL-1
p value
Doxycycline 0.093 0.111 0.315
Tetracycline 0.050 0.060 0.335
Minocycline 0.094 0.145 0.129
Co-trimoxazole 0.091 0.084 0.712
Clindamycin 0.066 0.085 0.594
Erythromycin 0.041 0.018 0.03

Ref: H-H. Tan et al. Br J Dermatol 2007;157:547-551.

In the report, teenagers expressed psychological distress over their acne, and they believed that hormonal factors, diet and hygiene were important factors in the causation of their acne. There is a need for accessible, accurate education on acne and its early and appropriate treatment.

Prevalence of antibiotic resistance in P. acnes in Singapore and the rest of the world is rising. The treatment strategy for acne vulgaris needs to be reviewed. Reliance on topical antibiotics needs to be curtailed and systemic antibiotics minimized. Topical benzoyl peroxide and retinoids use should be encouraged. Doxycycline has a low resistance profile and should be considered as a first-line antibiotic, where necessary.

The consequences of acne vulgaris can impact quality of life. An observational survey in Singapore (unpublished) on the psychosocial impact of acne scarring on 35 young adults in the National Skin Centre in Singapore showed that the mean age at which the first facial acne scars appeared was 19.8 years. Of those with scarring, 26% had mild scars and 57% moderate scars and 17% had severe scars (Figure 3).

Figure 3. Scars from acne vulgaris


Thirty-seven percent of these patients were self-conscious of their scars, with 26% feeling their acne scars affected their social activities. The mean dermatology quality of life index (DLQI) score for acne scars was 6.49. This is comparable to other debilitating skin conditions such as vitiligo (5.6), lichen planus (5.8), bullous pemphigoid (6.0), alopecia areata (6.2) and pityriasis rosea (6.6). This study showed that acne scaring has a significant negative effect on the quality of life of young adults, highlighting the need for increased public awareness through educational programmes. Early treatment is important in reducing the risk of scar development and the subsequent adverse psychosocial disabilities resulting from feelings of embarrassment, frustration and poor self-esteem.


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  2. Lello J, Pearl A, Arroll B, et al. Prevalence of acne vulgaris in Auckland senior high school students. N Z Med J 1995;108:287-9.
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  7. Tan HH, Goh CL, Yeo M. Antibiotic sensitivity of Propionibacterium acnes isolates studied in a skin clinic in Singapore. Arch Dermatol 1999;135:723.