Correspondence

Tretinoin for Hyperpigmentation in Black Patients

N Engl J Med 1993; 329:1503November 11, 1993

Article

To the Editor:

In their report (May 20 issue), Bulengo-Ransby et al. concluded that topical tretinoin therapy lightened postinflammatory hyperpigmentation; it also lightened normal skin in black persons to a minimal degree.1 The authors have demonstrated only that tretinoin is useful in the treatment of acne, nothing more. Acne was the actual diagnosis in 62 of the 68 patients in the study. In many patients, acne lesions cause postinflammatory hyperpigmentation. Any control or diminution of the underlying disease will result in less hyperpigmentation. Over time (40 weeks in this study), preexisting areas of postinflammatory hyperpigmentation resolve or fade.

Since hyperpigmentation also improved in over 50 percent of the patients using the vehicle cream, one might ask whether the patients were receiving oral antibiotic therapy as well. Other topical preparations, except for a sunscreen, were eliminated by the design of the study. Did the sunscreen alone result in improvement?

A more appropriate approach to the study of hyperpigmentation might be to compare the respective effects of the vehicle cream, hydroquinone, and hydroquinone with tretinoin on melasma or on hyperpigmentation after the resolution of either an allergic contact dermatitis or an irritant contact dermatitis. To assess the postinflammatory changes of acne, a comparison of benzoyl peroxide and a topical antibiotic with tretinoin and a topical antibiotic, each with or without sunscreens, seems more appropriate.

The darker the skin of a patient with acne, the more commonly one sees postinflammatory hyperpigmentation. The underlying erythema that may exaggerate the degree of perceived hyperpigmentation before treatment is less easily observed.

Elizabeth J. LaVoo, M.D.
467 W. Deming Pl., Chicago, IL 60614

1 References

1. 1

   Bulengo-Ransby SM, Griffiths CEM, Kimbrough-Green CK, et al. Topical tretinoin (retinoic acid) therapy for hyperpigmented lesions caused by inflammation of the skin in black patients. N Engl J Med 1993;328:1438-1443
   Full Text | Web of Science | Medline

Author/Editor Response

The authors reply:

To the Editor: Acne was the cause of postinflammatory hyperpigmentation in the majority of the patients we studied, although in 22 patients hyperpigmentation resulted from other causes, such as folliculitis, eczema, or irritation from shaving, either alone or in addition to acne. We did not assess the ability of tretinoin to improve acne, which has already been demonstrated. We assessed only the sequelae of this disease -- that is, postinflammatory hyperpigmentation, which is common and particularly troublesome in black patients. The careful designation of hyperpigmented lesions allowed us to monitor the treatment response of postinflammatory hyperpigmentation and not active acne lesions.

As the time course of our study demonstrates, postinflammatory hyperpigmentation resolves spontaneously over a 10-month period. However, topical tretinoin accelerates the resolution considerably (fivefold), with lightening of the lesions beginning after only one month of therapy. Only six patients were treated with oral antibiotics during the study (four in the vehicle group and two in the tretinoin group), thus making it unlikely that antibiotics contributed much to the lightening or fading of tretinoin-treated lesions as opposed to vehicle-treated lesions. Sunscreen was used by both treatment groups; thus, any improvement produced by sunscreen use alone would have been similar in the two groups. Erythema, although admittedly more difficult to see in black patients, did not masquerade as hyperpigmentation, since histologic studies confirmed hyperpigmentation in all cases.

We agree that future studies should address the question whether tretinoin alone will lighten or clear hyperpigmentation from other causes, such as melasma. Of particular interest are the mechanisms that underlie the ability of tretinoin to inhibit melanocyte activity.

Christopher E.M. Griffiths, M.D., M.R.C.P.
Stella M. Bulengo-Ransby, M.D.
John J. Voorhees, M.D.
University of Michigan Medical Center, Ann Arbor, MI 48109-0314