Search

Topical tretinoin (retinoic acid) may be an effective and safe treatment for hyperpigmented skin lesions in black individuals. Hyperpigmented skin lesions are dark, irregular spots that can occur after inflammation caused by acne, folliculitis, eczema or shaving irritation. Among 54 black individuals with hyperpigmented skin lesions, 24 were treated with topical tretinoin applied to the face or arms or both and 30 were treated with a placebo cream, or an inactive substance, every day for 40 weeks. Lesions were 40% lighter in the individuals treated with tretinoin after completion of treatment, compared with 18% lighter in the individuals treated with the placebo cream. Treatment with tretinoin reduced the melanin content of the lesions by 23%, compared with a 3% reduction after treatment with the placebo cream.

A 0.1 percent tretinoin cream applied to the skin may eliminate liver spots in some individuals. Liver spots are pigmented areas on the skin that are believed to be caused by long-term exposure to sunlight. Of 58 individuals with liver spots on their faces and arms, 28 applied the cream to affected areas every night, and 30 applied a cream that did not contain tretinoin. The appearance of their liver spots was assessed visually after two and four weeks of treatment and every month thereafter. A skin biopsy of a liver spot was performed in each individual before and after 10 months of treatment. After 10 months of treatment, significantly more patients in the tretinoin group experienced some lightening of their liver spots, compared with patients in the control group. Analysis of skin biopsies showed individuals using tretinoin had decreased pigmentation in the area of the liver spot.

A new synthetic retinoid analogue, adapalene (6-[3-(1-adamantyl)-4-methoxyphenyl]-2-naphthoic acid, CD271), which is relatively selective for retinoic acid receptor β, was noted to bean effective comedolytic agent in the rhino mouse model and to have clinical efficacy against acne. In pursuit of this observation, we studied the effects of CD271 on the development of erythema, spongiosis, and epidermal hyperplasia as well as other well-characterized markers of in vivo retinoid action after 4 d of occluded topical treatment. The objective of the study was to elucidate further those parameters associated with potential clinical efficacy. Twenty-five subjects were treated with 0.1% all-trans retinoic acid cream, all-trans retinoic acid vehicle, 0.1% CD271 gel, or CD271 vehicle under occlusion for 4 d. Only all-trans retinoic acid induced erythema (p <0.01 versus all other treatments). Similarly, histologic analysis revealed that epidermal hyperplasia and spongiosis were induced only by all-trans retinoic acid (p <0.01 versus all other treatments). By immunohistochemical analysis: all-trans retinoic acid increased expression of epidermal transglutaminase, involucrin, and calgranulin (p < 0.05 versus all other treatments). In contrast to these data, both CD271 and all- trans retinoic acid caused marked and significant (p <0.05) elevation of cellular retinoic acid-binding protein-II (CRABP-II) messenger ribonucleic acid steady-state levels as judged by quantitative RNA blot analysis. Although CD271 treatment did not lead to erythema or affect epidermal morphology, its ability to induce a marker of retinoid action (i.e., CRABP-II) was 70% the potency of all-trans retinoic acid. This study suggests that CRABP-H gene expression may be a more sensitive indicator of retinoid biologic activity in skin than are erythema or changes in epidermal morphology and differentiation. [ABSTRACT FROM AUTHOR]