2009 Volume 119 Issue 9 Pages 1795-1809
[Purpose] To clarify incidence and difference of gender and age in skin disorders of dermatological patients in the early 21st century in Japan. [Methods] Nationwide cross-sectional and seasonal multicenter study was conducted by 76 university hospitals, 55 district-based pivotal hospitals and 59 private clinics (190 clinics in total). In each clinic, information on diagnosis, age and gender was collected from all of the out-patients and in-patients visited on any one day of the second week of May, August and November 2007 and February 2008. Average high and low monthly temperature and humidity reports were collected from the Meteorological Agency. [Results] The information on 67,448 cases from 170 clinics (69 university hospitals, 45 district-based pivotal hospitals and 56 private clinics) participated in all of the 4 seasonal examination, was analyzed. Top 20 skin disorders were, in high incidence order, miscellaneous eczema, atopic dermatitis, tinea pedis, urticarial/angioedema, tinea unguium, viral warts, psoriasis, contact dermatitis, acne, seborrheic dermatitis, hand eczema, miscellaneous benign skin tumors, alopecia areata, herpes zoster/postherpetic neuralgia, skin ulcers (nondiabetic), prurigo, epidermoid cysts, vitiligo vulgaris, sebborheic keratosis, and drug eruption/toxicoderma. The vast majority (85.34%) of dermatological patients were covered under the top 20 disorders. Each disorder showed its own specific age distribution. The number of patients was correlated with average high and low monthly temperature in disorders such as atopic dermatitis, contact dermatitis, urticarial/angioedema, prurigo, insect bites and tinea pedis. Male-prone (psoriasis, erythroderma, diabetic dermatoses, e. t. c.) and female prone (erythema nodosum, collagen diseases, livedo reticularis/racemosa, hand eczema, e. t. c.) diseases were clearly evident. [Conclusion] This study apparently highlights the present situation of dermatological patients in the early 21st century of Japan. It is necessary to continue to perform the similar study periodically from social dermatological point of view.