Leyden J L
Department of Dermatology, Hospital of the University of Pennsylvania, Philadelphia 19104-4283.
J Am Acad Dermatol. 1994 Sep;31(3 Pt 2):S31-3. doi: 10.1016/s0190-9622(08)81264-9.
Fungal infections of the foot can be divided into three major varieties, all of which have differing pathophysiologic aspects with therapeutic implications. Interdigital infections involve an ecological interplay between dermatophytes and bacteria. Simple scaling types of infection are caused by dermatophyte invasion of the stratum corneum, whereas macerated, erosive infections are caused by selection and overgrowth of bacteria, particularly Brevibacterium epidermidis, Micrococcus sedantarius, and various gram-negative species. Bacterial production of methanethiol and other sulfur compounds leads to inhibition of dermatophytes and accounts for the lower recovery of dermatophytes from the most severe cases. Plantar surface infections consist of widespread, moccasin-type infection caused by Trichophyton rubrum and localized scaling infections with episodes of intense inflammation caused by Trichophyton mentagrophytes. The former is particularly associated with an atopic background. Therapy is difficult because of poor immune responses and difficulty in delivering a sufficient quantity of drugs to the lower layers of a thick stratum corneum. Intense inflammation in T. mentagrophytes infections is the result of an immune, contact allergic response to fungal antigens.
足部真菌感染可分为三大类，所有这些类型在病理生理方面都有所不同，且具有不同的治疗意义。指间感染涉及皮肤癣菌与细菌之间的生态相互作用。单纯鳞屑型感染是由皮肤癣菌侵入角质层引起的，而浸渍糜烂型感染则是由细菌，特别是表皮短杆菌、缓症微球菌和各种革兰氏阴性菌的选择和过度生长所致。细菌产生的甲硫醇和其他含硫化合物会抑制皮肤癣菌，这也是在最严重病例中皮肤癣菌恢复率较低的原因。足底表面感染包括由红色毛癣菌引起的广泛的拖鞋型感染，以及由须癣毛癣菌引起的局部鳞屑感染并伴有剧烈炎症发作。前者尤其与特应性背景相关。由于免疫反应较差以及难以将足够量的药物输送到厚角质层的下层，治疗较为困难。须癣毛癣菌感染中的剧烈炎症是对真菌抗原的免疫接触性过敏反应的结果。
