A Rare Case of Localized Hypertrichosis in Conjunction with Erythema Nodosum.

Acquired hypertrichosis can occur in local inflammation. Erythema nodosum (EN) is a hypersensitivity reaction to various underlying antigenic stimuli including Mycobacterium tuberculosis, which causes inflammation in the septa of subcutaneous fat. There were several case reports that describe the association of localized hypertrichosis (LH) with traumatic panniculitis and lupus panniculitis. To our knowledge, this is the first reported case of acquired LH associated with EN. Thus, EN can be added to the list of causes of localized hypertrichosis.

The Low-Fluence Q-Switched Nd:YAG Laser Treatment for Melasma: A Systematic Review.

Melasma is a common pigmentary disorder with a complex pathogenesis, of which the treatment is challenging. Conventional treatment often leads to inconsistent results with unexpected pigmentary side effects and high recurrence rates. Recently, the low-fluence Q-switched Nd:YAG laser (LFQSNY) has been widely used for treating melasma, especially in Asia. We reviewed literatures on the LFQSNY treatment of melasma published between 2009 and May 2022 to evaluate the efficacy and adverse events, including its combination therapy. A systematic PubMed search was conducted and a total of 42 articles were included in this study. It was hard to summarize the heterogenous studies, but LFQSNY appeared to be a generally effective and safe treatment for melasma considering the results of previous conventional therapies. However, mottled hypopigmentation has been occasionally reported to develop and persist as an adverse event of LFQSNY, which may be associated with the high accumulated laser energy. When used aggressively, even LFQSNY can induce hyperpigmentation via unwanted inflammation, especially in darker skin. Although few studies have reported considerable recurrence rates three months after treatment, unfortunately, there is a lack of the long-term follow-up results of LFQSNY in melasma. To enhance the effectiveness and reduce the adverse events, LFQSNY has been used in combination with other treatment modalities in melasma, including topical bleaching agents, oral tranexamic acid, chemical peeling, or diverse energy-based devices, which generally reduced side effects with or without significant superior efficacy compared to LFQSNY alone.

Erythema induratum of Bazin in a 10-year-old boy.

Erythema induratum of Bazin (EIB) is a form of tuberculid resulting from hypersensitivity to tuberculosis antigen. EIB occurs most commonly in middle-aged women and is not typically seen in children. Here, we present a rare case of EIB, presenting as a chronic nodular panniculitis, in a 10-year-old Korean boy.