Topical glucocorticoids and thinning of normal skin as to be assessed by ultrasound

Fluorescence spectroscopy as a tool to detect and evaluate glucocorticoid-induced skin atrophy

Topical glucocorticoid (GC) therapy has been successfully used in the treatment of several common cutaneous diseases in clinical practice for a long time, and skin atrophy is one of the most typical cutaneous side effects of this therapy. The aim of this study was to evaluate the potential of noninvasive fluorescence spectroscopy (FS) technique in the detection and classification of GC-induced skin atrophy. A total of 20 male Wistar rats were used in the experimental protocol under controlled environmental conditions and with free access to food. One group received topical application of clobetasol propionate 0.05% for 14 days to induce cutaneous atrophy (atrophic group) and the other (control) group received only vehicle application following the same protocol and schedule. Histological analyses and FS measurements with laser excitation at both 532 nm and 408 nm were obtained on days 1 and 15. The FS results were classified as "normal" or "atrophic" according by histological analysis. Fluorescence spectra obtained with excitation at 408 nm allowed a clear distinction between the control and atrophic groups, and were more informative than the those obtained at 532 nm. Our results reveal that, if correctly applied, FS allows noninvasive evaluation of corticosteroid-induced skin atrophy, and thus represents an important step towards better monitoring of undesirable side effects of cutaneous therapy.

Qualitative and quantitative assessment of the benefit-risk ratio of medium potency topical corticosteroids in vitro and in vivo: characterisation of drugs with an increased benefit-risk ratio

Corticosteroids are widely used for the treatment of inflammatory skin disorders. However, systemic and local adverse drug reactions, especially skin atrophy, are potential complications that limit their use. Several attempts have been made to increase the safety of topical corticosteroid treatment, including new application schedules, special vehicles and new agents. In particular, the group of hydrocortisone and prednisolone double esters, with prednicarbate as the first and most often prescribed representative, seem to be equipotent alternatives to the gold standard betamethasone 17-valerate with respect to anti-inflammatory activity. At the same time, these new agents induce less skin atrophy, which may result from a unique skin metabolism and a specific influence on the cytokine network in the epidermis and dermis. On the basis of these effects, a new approach to in vitro quantification of the benefit-risk ratio has been developed. As already suggested by investigations in human volunteers, the benefit-risk ratio of the new compounds appears to be increased. Therefore, recent research has focused on drugs that selectively modulate cytokine release.

Evaluation of the atrophogenic potential of different glucocorticoids using optical coherence tomography, 20-MHz ultrasound and profilometry; a double-blind, placebo-controlled trial

BACKGROUND

Skin atrophy is one of the main side-effects of topical corticosteroid therapy. Although the use of high-frequency ultrasound is an established method that has been studied previously, it allows measurements of the slow-reacting dermal thickness only.

OBJECTIVES

To investigate the decreasing epidermal thickness, which occurs earlier, we used optical coherence tomography (OCT), a high-resolution noninvasive imaging technique, and compared it with 20-MHz ultrasound and profilometry.

PATIENTS/METHODS

In this double-blind placebo-controlled trial 20 healthy volunteers applied four different corticosteroids and the cream base formulation as placebo to the volar part of both arms once a day over a 4-week period. The epidermal thickness, the dermal thickness and the skin surface roughness were assessed using OCT, high-frequency ultrasound and profilometry.

RESULTS

Each of the three methods allowed the detection and monitoring of significant corticosteroid-induced skin atrophy and its reversibility. The changes correlated with the potency of the steroids. The epidermal thickness decreased significantly in all test areas, even in the placebo and the untreated fields. As expected, the reduction in epidermal thickness was more pronounced and could be detected earlier by OCT than the reduction of dermal thickness using ultrasound. The epidermal surface roughness investigated using profilometry showed a slight smoothing.

CONCLUSIONS

OCT allows a simple, fast and noninvasive in vivo measurement of the epidermal thickness. To evaluate the atrophogenic potential of corticosteroids it is more suitable than high-frequency ultrasound as epidermal thickness decreases earlier. In addition, epidermal thickness is a more sensitive indicator of steroid atrophy as the degree of thinning is much higher compared with the dermal atrophy. Profilometry might give further information; however, it would not be suitable for clinical use as the results were generally less pronounced. In the future, OCT might be useful to detect corticosteroid-induced side-effects at the beginning for monitoring the therapy.

Adverse effects of topical glucocorticosteroids

Topical corticosteroids were introduced into medicine about 50 years ago. They represent a significant milestone in dermatologic therapy. Despite encouragement to report observed adverse drug reactions, the clinical practice of reporting is poor and incomplete. Likewise, adverse effects and safety of topical corticosteroids are neglected in the medical literature. The authors provide an updated review of their adverse-effect profile. Children are more prone to the development of systemic reactions to topically applied medication because of their higher ratio of total body surface area to body weight. Cutaneous adverse effects occur regularly with prolonged treatment and are dependent on the chemical nature of the drug, the vehicle, and the location of its application. The most frequent adverse effects include atrophy, striae, rosacea, perioral dermatitis, acne, and purpura. Those that occur with lower frequency include hypertrichosis, pigmentation alterations, delayed wound healing, and exacerbation of skin infections. Of particular interest is the rate of contact sensitization against corticosteroids, which is considerably higher than generally believed. Systemic reactions such as hyperglycemia, glaucoma, and adrenal insufficiency have also been reported to follow topical application. The authors provide an updated review of local and systemic adverse effects upon administration of topical corticosteroids, including the latest FDA report on the safety of such steroids in children.

LEARNING OBJECTIVE

At the completion of this learning activity, participants should be familiar with topical corticosteroids and their proper use.

The neutral red release assay: a review

The neutral red release (NRR) assay is a cytotoxicity test that can be used to measure the immediate toxic effects of test substances on the cell membrane, resulting in the leaking of intracellular contents. The assay has already been used for several years to evaluate the cytotoxicities of various kinds of products, such as cosmetics, pharmaceuticals, industrial chemicals and household products. It has undergone in-house validation by many companies, and has been found to be particularly useful for identifying substances that are potentially capable of causing adverse reactions on coming into brief contact with the eye or the skin at relatively high concentrations, such as might occur in an adventitious splash into the eye or onto the skin, followed by a quick rinse. Because of the relatively long existence of the NRR assay, its practicality and its proven usefulness for particular purposes, ECVAM decided to review the status of the method, in order to decide whether prevalidation and formal validation studies on the test might be profitable. The review of the status of the test was carried out by performing a comprehensive review of the literature, and by conducting a survey involving companies and institutes with experience in using the test. Both the review and the survey revealed that the assay could provide extremely valuable information when it was used for particular purposes, such as for the evaluation and comparison of immediate toxic effects on the eye or the skin caused by certain products or chemicals such as surfactants. Most of those who responded in the survey favoured a prevalidation/validation study.