Since 1953, 26 topical corticosteroids have been permitted for clinical use in Japan. The first topical corticosteroids used clinically in Japan were rather mild, for example, hydrocortisone. However, in recent years, the new corticosteroids are much more potent. This is undoutedly due to the fact that the more effective the agent is, the less time is required for treatment, and the more resistant lesions become to a cure. Untoward reactions such as suppression of the adrenal cortex function and local skin side effects seen with these potent, topical corticosteroids present a problem for clinician. Skin atrophy, redness, and telangiectasia are sometimes observed after a long duration of use of such corticosteroids. Rosacea-like dermatitis, so-termed by Steigleder (1968) and which usually occurs on the face of women, is sometimes seen in patients with a history of long term application of corticosteroids. Although these types of local side effects subside with time, long term application of such corticosteroids should be avoided. From above mentioned facts, development of an effective but mild topical corticosteroid has long been awaited. It is difficult for the physician to assess untoward reaction potential, because the patient might be using more than one corticosteroid during the course of treatment. Therefore, a method for prediction of untoward reaction potential has to be designed. Some workers have described the methodology of measurement of skin atrophy due to various corticosteroids. The data from animal experiments do not necessarily allow for a sufficient prediction of reactions in humans. This report is concerned with the assessment of local side effects such as skin atrophy, redness, telangiectasia on human skin. The test was performed on 16 healthy male volunteers. Two areas on the flexor aspect of each forearm were used as the test site for randomly allocated four test samples, namely; 0.3% prednisolone 17-valerate 21-acetate (PVA) ointment, its vehicle, 0.1% hydrocortisone 17-butyrate (HB) ointment and its vehicle. HB ointment was selected as the reference drug because; (1) it was reported that the adrenal cortex suppression due to HB was significantly weaker than that of betamethasone 17-valerate, in a double blind study conducted in Japan, and (2) the test drug, PVA, is a nonhalogenated corticosteroid, as is HB. The test samples were applied daily for six weeks every morning and evening, and an occlusive dressing was applied overnight. The thickness of skin at the test areas was measured prior to and each week during the test using a Harpenden skinfold caliper. Also, ocular inspection for the occurrence and the degree of redness, and telangiectasia and palpation for skin atrophy was made. The following results were obtained:
(1) Measurement of skin atrophy; the average skin thickness on the test area prior to application of test samples was 2.2mm. A decrease in skin thickness on the PVA and HB applied site was observed one week after the initiation of application and the degree of skin atrophy increased weekly. Two weeks after the initiation of application, the degree of skin atrophy due to HB was significantly higher than PVA. Four weeks after the discontinuation of application, the skin atrophy due to both corticosteroids returned to the initial value.
(2) Observation of redness, telangiectasia, and skin atrophy; four weeks after the initiation of application, redness was observed at HB and PVA applied sites in 6/16 volunteers. Six weeks after the initiation of application, redness was observed in 12/16 at the HB applied site and in 11/16 at the PVA applied site. A significantly higher degree of redness was evident at the HB applied site. Telangiectasia was observed in 8/16 at the HB applied site and in 7/16 at the PVA applied site. Skin atrophy was evident on palpation in 11/16 at the HB applied site and in 10/16 at the PVA applied site. (to be continued)
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