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Background and objectives The treatment of Riehl's melanosis, also known as pigmented contact dermatitis, is highly challenging. Intense pulsed light (IPL) and 1064 nm Q-switched Nd:Yag (QS-Nd:YAG) laser are reported to have some efficacy. However, no single effective treatment has yet been identified. In this study, we demonstrated the efficacy and safety of the non-ablative 1927 nm fractional thulium fiber laser (TFL, LASEMD™; Lutronic Corp., Goyang, Korea) for patients with Riehl's melanosis. Study design/materials and methods A retrospective chart and photographic review of nine patients with Riehl's melanosis, who had received at least three sessions of TFL treatment, was performed. Before the start of TFL treatment, combination treatment with a topical cream containing hydroquinone, low-fluence QS-Nd:YAG laser, pulsed dye laser, and IPL was used with variable and discouraging effects. Seven patients were treated on the face and two patients on the neck with three to seven sessions at 1-month intervals. Clinical improvement was assessed using clinical photos taken before and after every treatment session according to dermal pigmentation area and severity index (DPASI) and a quartile grading scale by two blinded dermatologists. Results Patients underwent three to seven sessions of TFL treatment depending on severity of pigmentation. Of nine patients, six demonstrated a clinical improvement of 51%-75%, one demonstrated an improvement of 76%-100%, and two showed an improvement of 26%-50% after treatment. The DPASI was significantly decreased from 9.55 to 5.25 on average. Melanin index was decreased after treatment in two patients whose melanin index were measured at initial visits. Treatment-related adverse events, such as scarring or postinflammatory hyperpigmentation (PIH), were not observed in all patients except for transient erythema and swelling. Conclusions This report suggests that TFL could be an alternative and/or additive treatment option for hyperpigmentation in intractable Riehl's melanosis and might be a promising treatment for PIH caused by any reason including Riehl's melanosis. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

Severe alopecia areata (AA) can have an unpredictable clinical course and become refractory to contact immunotherapy. Novel treatment options include low-dose interleukin-2 and Janus kinase inhibitors; however, these treatments are still under investigation. Therefore, we evaluated the efficacy and safety of intramuscular (i.m.) triamcinolone acetonide (TAC) as a rescue therapy for refractory AA. We retrospectively analysed efficacy, adverse effects and relapse rate of i.m. TAC monthly in 27 patients with refractory AA. We defined AA as refractory if the patient showed an unsatisfactory response to both systemic treatment (not i.m. TAC) and the consecutive diphenylcyclopropenone immunotherapy. The initial systemic treatment of other forms of corticosteroids and/or cyclosporin was used to control extensive AA involving more than 25% of the scalp. Administration of i.m. TAC for 3-6 months resulted in a 63.0% response rate, and all patients showed inactive disease after treatment. Final hair regrowth negatively correlated with initial scalp involvement (Spearman r = -0.595, P = 0.001). All patients showed complete recovery of adrenocortical reserve within 3 months after the last injection. Adverse effects of systemic steroid therapy were observed only in female patients (dysmenorrhea and osteoporosis). i.m. TAC may provide a valuable therapeutic option to manage active hair loss and facilitate hair regrowth in refractory AA, especially in male patients.

Extracellular adenosine 5ʹ-triphosphate (ATP) is a well-known inflammasome-activating signal. Emerging evidence demonstrates a critical role for inflammasome activation in vitiligo pathogenesis. However, the specific molecular mechanism of inflammasome-dependent melanocyte degeneration in vitiligo is still not clear. This study presents how extracellular ATP, released from keratinocytes by oxidative stress, affects melanocyte survival in vitiligo skin. H2O2-induced oxidative injury increased ATP release from keratinocytes and skin tissues. The high concentration of extracellular ATP induced both ROS production and cell death in melanocytes. Treatment with ATP caused the activation of caspase-1 as well as the production of active forms of IL-1β and IL-18 via P2X7 receptor in keratinocytes and melanocytes. Lesional and perilesional skin of vitiligo showed higher levels of ATP as well as upregulation of active caspase-1 compared with nonlesional skin, suggesting its possible role in inflammasome activation in vitiligo. Moreover, the elevated expression of CXCL9 in keratinocytes, mediated through ATP/P2X7 receptor–dependent inflammasome activation, was responsible for CLA+CD8+ T-cell chemotaxis into the skin. These results demonstrate that extracellular ATP as a danger signal activates the inflammasome pathway and increases cutaneous chemotaxis of CD8+ T cells via CXCL9 in vitiligo. Therefore, targeting ATP-P2X7 signaling may be a potential strategy for vitiligo treatment.

Phytophotodermatitis is a condition that occurs by contact with plants containing phototoxic agents such as furocoumarins and psoralens with subsequent ultraviolet exposure. Phytophotodermatitis typically presents as sharply defined erythematous patches with occasional blistering, sometimes accompanied with pain or itching sensation. In some cases, however, sudden appearance of asymptomatic hyperpigmentation can be the only clinical finding of phytophotodermatitis. Here, we present two patients with sudden development of asymptomatic pigmentation on their hand without preceding inflammation by the contact with citrus fruits containing photosensitizers and subsequent exposure to strong sunlight. As like these patients, phytophotodermatitis can present with only pigmentation without noticeable inflammation especially in dark skinned people. In such cases, physician can sometimes have difficulty in diagnosis of phytophotodermatitis. Therefore, it is important to consider the possibility of phytophotodermatitis through careful history taking, especially in patients who have abruptly developed well-defined hyperpigmentation on sun-exposed areas, to avoid unnecessary test and treatment.