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Background Nail involvement in lichen striatus (LS) is rare and has not been documented

BackgroundCholinergic urticaria is a type of physical urticaria characterized by heat-associated wheals. Several reports are available about cholinergic urticaria; however, the clinical manifestations and pathogenesis are incompletely understood.ObjectiveThe purpose of this study was to investigate the clinical characteristics of cholinergic urticaria in Korea.MethodsWe performed a retrospective study of 92 patients with cholinergic urticaria who were contacted by phone and whose diagnoses were confirmed by the exercise provocation test among those who had visited The Catholic University of Korea, Catholic Medical Center from January 2001 to November 2010.ResultsAll 92 patients were male, and their average age was 27.8 years (range, 17~51 years). Most of the patients had onset of the disease in their 20s and 30s. Non-follicular wheals were located on the trunk and upper extremities of many patients, and the symptoms were aggravated by exercise. Eight patients showed general urticaria symptoms and 15 had accompanying atopic disease. Forty-three patients complained of seasonal aggravation. Most patients were treated with first and second-generation antihistamines.ConclusionDermatologists should consider these characteristics in patients with cholinergic urticaria. Further investigation and follow-up studies are necessary to better understand the epidemiological and clinical findings of cholinergic urticaria.

Skin is constantly exposed to physical and chemical stressors. The exposure of keratinocytes to ultraviolet B (UVB) irradiation causes epidermal damage via induction of apoptosis. Erythroid differentiation regulator 1 (Erdr1) modulates growth and survival of cells under various stressful conditions, but the function of Erdr1 in human keratinocyte apoptosis has not been investigated so far. Here, we investigated the effect of Erdr1 on UVB-induced apoptosis in human keratinocytes and also examined the underlying regulatory mechanism. First, Erdr1 expression was detected in human primary keratinocytes and normal human skin tissues. Expression of Erdr1 was enhanced in human keratinocytes following UVB irradiation. Knock-down of Erdr1 led to resistance to UVB-induced apoptosis. Also, Erdr1 overexpression increased UVB-induced apoptosis and induced caspase-3 activation. Furthermore, the extracellular signal-regulated kinase (ERK) inhibitor PD98059 and the p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580 significantly reduced Erdr1 expression following UVB irradiation. These results indicate that UVB induces Erdr1 via a MAPK-dependent mechanism. Taken together, these findings suggest that Erdr1 has a role as a proapoptotic factor in human keratinocytes and acts via ERK and p38 MAPK pathways. Therefore, Erdr1 may be a potential therapeutic target to reduce apoptosis in keratinocytes in conditions such as psoriasis and skin cancer.