Isolated hypohidrosis: pathogenesis and treatment.

BACKGROUND: Hypohidrosis can result in heat injury, a potentially fatal condition. The majority of hypohidrosis cases have no associated abnormalities or secondary causes, and are termed "isolated hypohidrosis". These are clinically divided into miliaria profunda (MP), acquired idiopathic generalized anhidrosis (AIGA) and idiopathic partial hypohidrosis (IPH). The pathogenesis of isolated hypohidrosis remains largely unknown and there is no established effective treatment. OBJECTIVES: To elucidate the pathogenesis of isolated hypohidrosis using in vivo high-definition optical coherence tomography (HD-OCT) imaging and assess the therapeutic profile of oral retinoids for this condition. MATERIALS & METHODS: We conducted a retrospective analysis on all patients with isolated hypohidrosis in our neuro-dermatology clinic over a 5.75-year period. All patients routinely underwent standardised exercising and whole-body starch-iodine testing, followed by non-invasive HD-OCT skin imaging. Patients' demographics, disease characteristics, histology and treatment history were analysed. RESULTS: Of the 51 patients identified with isolated hypohidrosis; 23 were diagnosed with MP, 14 with AIGA, and 14 with IPH. In these patients, HD-OCT imaging led to the identification of sub-stratum corneal hypo-refractile material with underlying dilated sweat ducts, not present in healthy controls. The size of this material was most pronounced in MP, followed by AIGA, and then IPH. Post-treatment, the material decreased in size. Treatment response was reported in 90.6% patients with isotretinoin and 75.0% with acitretin. No recurrence has been reported to date. Side effects were largely anticipated and common. CONCLUSION: The pathogenesis of isolated hypohidrosis involves obstruction of sweat orifices at the stratum corneum. Treatment with oral retinoids, particularly isotretinoin, is effective and safe.

Effectiveness of Paint Psoralen and Ultraviolet-A in Alopecia Areata - Our Experience in the National Skin Center.

BACKGROUND: Alopecia areata (AA) is usually a benign cause of patchy hair loss that often resolves within a few weeks to months. Most treatment modalities are ineffective in the treatment of severe AA. The use of paint psoralen and ultraviolet-A (PUVA) in the treatment of patients with severe forms of AA has been reported in the literature. AIMS AND OBJECTIVE: The aim of this study was to evaluate the effectiveness of paint PUVA therapy in the treatment of AA in Singapore. MATERIALS AND METHODS: We performed a 10-year retrospective analysis of patients who underwent paint PUVA for AA. We evaluated patient demographics and treatment outcomes in the form of percentage change in baseline severity of alopecia tool score and final amount of hair regrowth and relapse rate. RESULTS: Ten patients were included in this study. With paint PUVA therapy, significant hair regrowth was seen in six patients. Paint PUVA therapy in our study showed minimal side effects. CONCLUSION: PUVA gives fair response in AA in a reasonable time as per our center's experience in Singapore.

Clinical Characteristics of Patients With CRVO in One Eye With Subsequent RVO in The Fellow Eye: A Retrospective Observational Study.

BACKGROUND AND OBJECTIVE: To compare risk factors in patients with a central retinal vein occlusion (CRVO) in the first eye and a subsequent retinal vein occlusion (RVO) in the fellow eye versus those with only unilateral CRVO. PATIENTS AND METHODS: Records of patients who presented to the Duke Eye Center with unilateral CRVO were evaluated. Logistic regression models were performed to identify potential covariates of subsequent development of RVO in the fellow eye. RESULTS: Of the 287 patients with CRVO in one eye, 31 (10.8%) developed an RVO in the fellow eye during a mean ± standard deviation follow-up of 36.7 months ± 38.86 months. The conversion rate of unilateral-to-bilateral RVO was 3.4% per year. Several comorbidities were observed to be unique to 25.8% of patients with bilateral RVO. Patients who used oral pentoxifylline (P = .008) or those who had an ischemic CRVO in the first eye (P = .001) were less likely to develop an RVO in the fellow eye. CONCLUSION: This information may be used to develop a predictive model to assess the risk of developing bilateral RVO in patients with unilateral CRVO. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:444-449.].