Annular infectious dermatoses.

Annular configuration is conspicuous in the clinical manifestation of many skin diseases and can be helpful for the diagnosis and differential diagnosis. Variations may include arciform, ring-form, annular, circinate, serpiginous, gyrated, polycyclic, targeted or figurate forms, in different colors, sizes, and numbers, with various textures and surfaces. In infectious dermatoses, the annular reactions can be specific or nonspecific, while the underlying mechanisms remain largely unknown. In the specific reactions caused by direct invasion of the pathogens, the contest between the centrifugal outspread of the infectious agents and the centripetal impedance of the host immune response is supposed to determine the final conformation. Examples include erythema infectiosum, orf, erythema multiforme, and pityriasis rosea of viral origin. Bacterial infections that may display annular lesions include erythrasma, erythema (chronicum) migrans of Lyme borreliosis, secondary syphilis, cutaneous tuberculosis, and leprosy. Superficial mycosis, such as dermatophytosis, candida intertrigo, tinea imbricata, and subcutaneous mycosis, such as chromoblastomycosis, and algae infection protothecosis, are characterized by annular progression of the skin lesions. The creeping serpiginous extension is an alarming sign for the diagnosis of cutaneous larva migrans. A better understanding of the virulence and pathogenicity of the pathogens and the way and type of immune response will help to clarify the pathogenesis.

Leprosy in the Department of Dermatology, Chang Gung Memorial Hospital at Kaohsiung from 1988 to 2004: a clinical and histopathologic study of 13 cases.

BACKGROUND: Leprosy has long been in Taiwan, but it has never been eradicated. Incidental cases are easily overlooked nowadays because most younger dermatologists are unfamiliar with this disease. METHODS: We review and analyze 13 cases diagnosed as leprosy at the Department of Dermatology, Chang Gung Memorial Hospital at Kaohsiung from 1988 to 2004, all of which were histopathologically proven. RESULTS: The ages of the 13 recruited patients ranged from 31 to 73 (mean, 58.6) years, without a gender preference (male: female, 7:6). Two male patients were under 40 years old; one was a foreign worker from Thailand and the other was a local person in Penghu working as the chief officer on a fishing boat. The most-common clinical subtype was lepromatous leprosy (5/13), followed by borderline lepromatous leprosy, borderline tuberculoid leprosy, and tuberculoid leprosy (each 2/13), and then borderline leprosy and indeterminate leprosy (each 1/13). The initial clinical impression before the histopathological diagnosis included granuloma annulare, generalized eczema, lymphoma, syphilis, papular urticaria, cutaneous tuberculous infection, Sweet's syndrome, erythema annulare centrifugum, and hematoma. Most of these patients only received irregular treatment after the diagnosis was made and were soon lost to follow-up. CONCLUSIONS: With increasing numbers of foreign workers and immigrants living in Taiwan in recent years, leprosy seems to have become a challenging diagnosis for younger dermatologists. Dermatologists should keep this ancient disease in mind and not overlook it. Because of the necessity of prolonged medication, complete treatment and long-term follow-up of leprosy cases will remain a major problem in public health.