Chondrodermatitis nodularis helicis is a painful condition that is difficult to treat. Histologically, CDNH consists of a nodule of degenerate homogeneous collagen surrounded by vascular granulation tissue with an overlying acanthotic epidermis, and there may be a central ulcer through which the damaged collagen is extruded. In nearly all cases there is inflammation and fibrosis of the underlying perichondrium, and degenerative changes may be seen in the cartilage. Many authors view the condition as an example of transepidermal elimination of altered connective tissue.8 Pressure and a compromised local blood supply are believed to be key factors in the development and recurrence of CDNH.9 Various theories regarding its etiology have been published about the initial event: that it is the result of (1) cartilaginous changes, (2) hyperkeratosis leading to the perforation, (3) cold or poor circulation, and/or (4) traumatic injury to the collagen.10 As to the efficacy of PDT for CDNH, it could act on several pathogenic factors. Our hypothesis is based on (1) its anti-inflammatory and immunomodulatory action, (2) its effect on vascularization or on collagen, and (3) a possible chondroprotective effect. In skin areas treated with aminolevulinic acid (ALA)-PDT, inflammatory reactions seem to slow down because of the resident macrophages and mast cells death and the slow recovery to cytokine responsiveness of the surviving cell population.11 It is generally accepted that PDT causes acute inflammation, but it is also thought that the judicious application of acute inflammation can interrupt the process of chronic inflammation and stimulate healing.12 Topically applied methyl aminolevulinate sensitizes mainly keratinocytes; using protocols of irradiation, which may induce sublethal cellular effects, several cytokines are released by those cells, possibly resulting in a change of cytokine equilibrium in the inflammatory milieu and finally leading to a disruption of the chronic inflammation present in CDNH.13 In relation to the role of topical PDT on improving blood supply in CDNH, it has been proved that blood perfusion is increased immediately after irradiation and persists up to a week.14 Regarding the effect on collagen, no changes in synthesis of collagen type II, the major connective tissue component of ear cartilage, has been observed when chondrocytes were treated in vitro with ALA-PDT.15 Nevertheless, Park et al16 have demonstrated that after 1 month of treatment with ALA-PDT in human skin, the total collagen volume in the dermis significantly increased, with expression of type I and III procollagen; this could explain the excellent cosmetic results in our patients.