Evaluation of the atrophogenic potential of hydrocortisone 1% cream and pimecrolimus 1% cream in uninvolved forehead skin of patients with atopic dermatitis using optical coherence tomography.

Topical corticosteroids are widely used to treat atopic dermatitis (AD), but their anti-inflammatory mode of action can be accompanied by several unwanted side effects including skin atrophy and telangiectasia. In this 8-week, investigator-blinded, intraindividual right-left comparison study with patients with mild-to-moderate AD, hydrocortisone 1% cream (HCT) was applied twice daily for 4 weeks on one side of forehead skin without clinical signs of AD and pimecrolimus 1% cream (PIM) on the other. Epidermal and dermal thickness were assessed by optical coherence tomography (OCT) and high-frequency ultrasound, respectively. Skin atrophy and telangiectasia were assessed by contact dermatoscopic photography (Dermaphot(®)). Treatment with HCT leads to a significant decrease in epidermal thickness after only 2 weeks of treatment, while the decrease in PIM-treated sites was less pronounced and was not statistically significant. By 4 weeks after the end of treatment, epidermal thickness returned to baseline values. No dermal thinning or development of telangiectasia could be observed by means of ultrasound or Dermaphot(®), respectively. In summary, this study indicates that a 2-week single course of topical treatment with a mildly potent steroid can cause transient epidermal thinning, an effect not seen in the PIM group. The slight decrease with PIM - although not significant - could be due to normalization of the increased skin thickness caused by a subclinical inflammation in AD. This study suggests that PIM may be safer for treatment of AD in sensitive skin areas like the face, especially when repeated application is required.