University of Michigan
Department of Pediatrics
Evidence-Based Pediatrics Web Site

Question

• A 15 y/o adolescent comes into the clinic after failing over-the-counter treatment for acne.  How can we help?   Which is the most safe and efficacious keratolytic to add to the regimen?

Clinical Bottom Lines

1. Acne is very common in childhood—early and effective treatment may help prevent later sequale such as pitted scars and psycho-social issues.
2. According to one randomized, investigator blinded study, adapalene 0.1 % gel is significantly superior to tretinoin 0.025% gel in decreasing total lesion counts after 12 weeks of treatment.¹

Summary of Key Evidence

1. Starting as early as 2 weeks, adapalene gel produced a numerically greater lesion reduction than did the tretinoin gel.¹  By week 12, the mean percent reduction in the adapalene group was 49% vs. 37 % in the tretinoin group for total lesions with a p value of <0.01.  The reduction of non-inflammatory lesions (open and closed comedones) was also significantly greater in the adapalene group. 
2. The side effect profiles were similar (erythema, scaling, dryness and burning) to retinoid therapy, but were significantly less severe (p<0.05), particularly for erythema.  Less irritating symptoms were noted even by week 2.
3. No significant systemic symptoms were noted, and no quantifiable amounts of adapalene were noted on plasma samples.

Additional Comments

• Although this study does indeed indicate that there is a mean percentage reduction with adapalene which is greater than that of tretinoin, and does allude to the investigators overall impression of improvement by the global assessment, it would be interesting to see how this correlates to patient satisfaction.
• Adapalene (6-[3-(1-adamantyl)-4-methoxyphenyl]-2-naphothoic acid) is a synthetic compound which binds to the nuclear and cytosolic retinoic acid receptors in a different way than tretinoin. It is a potent modulator of cellular differentiation, keratinization and inflammation.
• Neither tretinoin nor adapalene are photosensitizers. Exposure to sun worsens the irritation, making them photoirritants. Tretinoin chemically oxidizes in sunlight, where adapalene is chemically stable, but both are still recommended to be applied at night.
• Both adapalene and tretinoin have at least additive, and possibly synergistic effects when used with other anti-acne medications (such as Benzoyl Peroxide and antibiotics).
• As always at the bottom line….COST: Differin 0.1 % gel: 15 G = $ 33.80 Tretinoin gel: 15 G = $ 33.00

Citation

1. Shalita A.  A comparison of the efficacy and safety of adapalene gel 0.1% and tretinoin gel 0.025% in the treatment of acne vulgaris: A multicenter trial.  Journal of the American Academy of Dermatology, 1996; 34:482-485.
2. Weiss J.  The evolving role of retinoids in the management of cutaneous conditions.  Journal of the American Academy of Dermatology, 1998; 39:PS050-054.
3. Lucky A.  Predictors of severity of acne vulgaris in young adolescent girls: Results of a five-year longitudinal study.  Journal of Pediatrics, 1997; 130:30-39.
4. Ellis C.  Comparison of adapalene 0.1% solution and tretinoin 0.025% gel in the topical treatment of acne vulgaris.  British Journal of Dermatology, 1998; 139(Suppl. 52):41-47.

CAT Author: Goldie Mantel, MD

CAT Appraisers: John Frohna, MD

Date appraised: May 15, 2000