Background: Scalp psoriasis is a major therapeutic challenge due to the hindrance caused by hair. Treatment with the 308-nm excimer lamp is purported to provide many benefits over conventional phototherapy. This retrospective study evaluates the efficacy, safety, and effective dosage of 308-nm excimer light in the treatment of scalp psoriasis. Methods:We retrospectively reviewed the medical records of patients with scalp psoriasis who received treatment with 308-nm excimer light. Clinical and epidemiological data as well as details regarding treatment were statistically analyzed to determine the treatment outcomes.Results: Twenty patients with scalp psoriasis were included in the study. Their mean age was 47.45 ± 17.93 years. Eleven patients responded to treatment at the end of 10 sessions. The median baseline Psoriatic Scalp Severity Index (PSSI) was 12 (range, 3-32). At the end of the protocol, the median PSSI was 4.5 (range, 0-24), indicating a statistically significant reduction (P < 0.001). Common adverse effects included erythema, irritation, and desquamation. Conclusion:The 308-nm excimer light appears to be an effective and safe modality that requires short treatment time. The modality could be considered as an alternative or adjuvant treatment for scalp psoriasis. K E Y W O R D S excimer lamp, excimer laser, excimer light, phototherapy, scalp psoriasis | 173 RATTANAKAEMAKORN ET Al. How to cite this article: Rattanakaemakorn P, Phusuphitchayanan P, Pakornphadungsit K, Thadanipon K, Suchonwanit P. Efficacy and safety of 308-nm excimer lamp in the treatment of scalp psoriasis: a retrospective study.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare tumor that affects elderly individuals and presents a poor prognosis. Skin is the most common site of involvement, accounting for 89% of the cases. Extracutaneous organs, especially bone marrow, lymph nodes, and peripheral blood, can be involved at the time of diagnosis. We report a case of BPDCN in a child, presenting with a cutaneous lesion mimicking lymphoma or leukemia cutis. The histologic findings revealed a dense diffuse infiltration by monomorphic agranular medium-sized blast cells with sparing of the grenz zone, whose first immunophenotypic profile raised the possibility of diagnosing B lymphoblastic lymphoma or leukemia. However, the absence of CD10 expression and strongly positive expression for CD4, CD56, CD45RA, and the plasmacytoid dendritic cell-associated antigens, including CD123, supported the definite diagnosis of BPDCN. The patient responded well to a systemic combination chemotherapy regimen, modified from the Associazione Italiana Ematologia Oncologia Pediatrica (AIEOP) protocol for anaplastic large cell lymphoma (ALCL), that differed from the established recommendation using ALL protocol. Owing to the patient’s excellent treatment outcome, this regimen could represent an effective alternative regimen for BPDCN in children.

Epidermolytic ichthyosis (EI) is a rare genodermatosis disorder. We report a 39-year-old woman with EI, who presented with generalized erythroderma since birth, followed by generalized hyperkeratosis later in life. The physical examination revealed generalized hyperkeratosis without blistering or erosion. The histopathological studies revealed hyperkeratosis with parakeratosis and psoriasiform hyperplasia, without significant epidermolysis. The Sanger sequencing revealed a missense mutation—c.467G>A (p.Arg156His)—in the KRT10 gene, confirming the diagnosis of EI. The genotype-phenotype correlations in EI patients are multifactorial. Thus, molecular analysis can confirm the diagnosis in cases of an unclear medical history or histological inconclusiveness.