Actinic Prurigo

Dermatologist shines a light on the latest research in photocontact dermatitis SAN DIEGO, March 8, 2024 /PRNewswire/ -- Sun sensitivity and related skin conditions are often misunderstood. Foods, medications, and skincare products can trigger symptoms like itching, redness, blistering, or burning. One of the most common conditions is photocontact dermatitis, a skin reaction occurring when certain substances come into contact with skin that is exposed to the sun. "Sun sensitivity is a common condition that can negatively impact a person's quality of life," said board-certified dermatologist Brandon Adler, MD, FAAD, an assistant professor of dermatology at Keck School of Medicine at the University of Southern California in Los Angeles, speaking at the American Academy of Dermatology's 2024 Annual Meeting. For many people, sun sensitivity is caused by the things they come into contact with, said Dr. Adler. If you develop rashes, blisters, or skin darkening after making a margarita or chopping vegetables for a salad, some of the ingredients may be to blame, said Dr. Adler. Your skin reaction could be caused by handling fruits and vegetables such as lime, figs and celery, or coming into contact with plants like hogweed and St. John's wort. Certain pain relief medications that are applied to the skin may also cause a photosensitive reaction, as can medications taken by mouth, such as some blood pressure medications like hydrochlorothiazide. While medications applied directly to the skin only cause a rash in the area of the body where it was applied, if a medication taken by mouth causes photosensitivity, it can cause a rash over any part of the body that was not protected from the sun. Reactions often appear as an itchy rash or severe sunburn on areas of the body most exposed to the sun, such as the face, neck, arms, or legs, according to Dr. Adler. To determine the cause of sun sensitivity reactions, dermatologists must consider a variety of individual factors, such as various product exposures and medical history, and less frequently bloodwork or a biopsy of the affected area of the skin. "While we will often prescribe anti-inflammatory medications to treat photocontact dermatitis, the primary treatment is identifying and avoiding the irritant or allergen," said Dr. Adler. "In many cases these are reversible reactions, so if the patient stops using the substance causing the reaction, then they will stop having symptoms and won't need ongoing treatment." Many people incorrectly assume that certain types of sun sensitivity only affect older people with lighter skin types, but recent research indicates that younger people and those with darker skin types are more susceptible than previously believed, according to Dr. Adler. New studies suggest that people with darker skin types are susceptible to two other types of photosensitivity, he said. The first is polymorphous light eruption (PMLE), which appears as tiny bumps or rashes that come and go with sun exposure. The second is chronic actinic dermatitis, which causes year-round rashes affecting the sun-exposed parts of the body due to light sensitivity. The exact causes of PMLE and chronic actinic dermatitis are not fully understood, but they are believed to involve an abnormal immune response to sunlight. While it is important for everyone to protect themselves from the sun, Dr. Adler noted that those with sun sensitivity need to be particularly mindful to seek shade, wear sun-protective clothing, and apply a broad-spectrum, water-resistant sunscreen with an SPF of 30 or higher. "If you notice a rash or blistering on your body after being in the sun, it's important to see a board-certified dermatologist, who can determine whether you have a sun-related skin disorder," said Dr. Adler. "No two patients are the same. A board-certified dermatologist can determine what is causing your sun sensitivity and provide a treatment option that works best for your condition." To find a board-certified dermatologist in your area, visit aad.org/findaderm. More Information Eczema Types: Contact Dermatitis Causes AAD B-Roll Library About the AAD Headquartered in Rosemont, Ill., the American Academy of Dermatology, founded in 1938, is the largest, most influential and most representative of all dermatologic associations. With a membership of more than 20,800 physicians worldwide, the AAD is committed to advancing the diagnosis and medical, surgical, and cosmetic treatment of the skin, hair, and nails; advocating high standards in clinical practice, education and research in dermatology; and supporting and enhancing patient care because skin, hair, and nail conditions can have a serious impact on your health and well-being. For more information, contact the AAD at (888) 462-DERM (3376) or aad.org. Follow @AADskin on Facebook, TikTok, Pinterest and YouTube and @AADskin1 on Instagram. SOURCE American Academy of Dermatology

随着炎炎夏日到来，气温和湿度增加，各种蚊虫纷沓而出，许多皮肤病也逐渐进入了高发季。本文简单总结了夏季好发的几种常见皮肤病。手足口病手足口病是由肠道病毒（enterovirus，EV）感染引起的一种儿童常见传染病，5 岁以下儿童多发。临床表现：皮疹好发于指/趾背面或侧缘，初为紫红色斑丘疹，中央可出现白色水疱。口周、臀部也可出现丘疹、水疱，甚至全身泛发，伴有口腔溃疡。少数患儿有发热，极少数可出现系统并发症而病情危重。图 1. 常见手足口病皮损治疗原则：以隔离、观察和对症处理为主。注意隔离，避免交叉感染。详细诊疗、用药内容扫描二维码即可免费看足癣足癣是指由皮肤癣菌（dermatophytes）引起的足部浅表真菌感染。临床表现：主要累及趾间、足跖及侧缘，皮损可蔓延至足背及踝部。根据皮损形态，足癣一般分为水疱型、间擦糜烂型、鳞屑角化型等，临床不同阶段几种类型可以同时存在。1）水疱型：通常见于足跖中部或趾间皮肤。以成群或散在分布的小水疱为主，疱壁厚，疱液清；水疱干燥吸收后发生脱屑。初期常有明显瘙痒或刺痛感。2）间擦糜烂型：趾间糜烂、浸渍发白。除去表面浸渍发白部分，下方可见红色糜烂面，有时伴少量渗液。瘙痒感明显。夏季多发。3）鳞屑角化型：皮损多累及足跖，大片表皮增厚、粗糙、干燥脱屑，自觉症状轻微。治疗原则：足癣的治疗目标是清除病原菌，快速解除症状，防止复发。外用药、口服药或二者联合方案均可选用。鳞屑角化型足癣，常用的外用药物局部渗透性不佳，治疗较其他类型更困难。如果没有系统用药禁忌症，建议联合口服抗真菌药物治疗。详细诊疗、用药内容扫描二维码即可免费看蜱虫叮咬（莱姆病）莱姆病是一种蜱媒细菌感染性疾病，是螺旋体属伯氏疏螺旋体（Borrelia burgdorferi）感染的结果。由硬蜱传播。临床表现：与莱姆病相关的典型皮疹称为游走性红斑。呈靶型损害，局部红斑从被叮部位向周围扩散开来（图 2）。大约一半的神经莱姆病患者报告没有皮疹，可能是因为原发感染发生在不可触及的部位或发际线以下。皮损通常在被叮后 7～10 天出现，通常会自发消退。图 2. 游走性红斑：与疏螺旋体病相关的典型皮疹在接触蜱后 4～6 周，大约 5% 的未治疗的游走性红斑患者会发展成神经莱姆病，其中超过 95% 的患者在感染后 6 个月内出现神经莱姆病的症状。治疗原则：大多数神经莱姆病例在 3～6 个月内无需治疗即可痊愈。抗生素有助于加速清除细菌和阻止感染进一步发展，且能迅速改善病人的症状，尤其是疼痛。详细诊疗、用药内容扫描二维码即可免费看多形日光疹多形日光疹是最常见的一种光照性皮肤病。临床表现：在前胸「V」区、手背、上肢伸侧及妇女小腿等暴露部位出现丘疹、水疱、斑块或苔藓化的皮疹，自觉瘙痒。日光照射后数小时或数天出现皮疹，停止照射后 1 周左右皮疹可完全消退不留瘢痕。病情反复发作，部分患者的皮疹最后可自然消失。图 3. 多形性日光疹：右前臂伸侧粉红色丘疹和斑块 [1] 治疗原则：轻型多形日光疹仅需限制光暴露时间，使用遮光衣物以及遮光剂；不能起效时，局部使用糖皮质激素软膏；再无效时则可短期使用抗组胺药物。较严重的患者可考虑局部治疗、系统治疗、硬化治疗及光疗。详细诊疗、用药内容扫描二维码即可免费看水痘水痘是由水痘-带状疱疹病毒感染引起的儿童常见传染病。临床表现：水痘皮肤损害最初出现在面部和躯干，开始为红色斑疹，并扩散至身体其余部分。在 12-14 天内进展为丘疹、水疱、脓疱，最后结痂。典型表现是同一时期可同时出现四种不同形态的皮疹。口咽部可出现一些病变。患者通常主诉强烈瘙痒。除皮损外临床常见表现：1-2 天前出现皮肤表现的低热，腹痛、头痛、厌食、咳嗽和鼻炎、咽喉痛等。图 4. 水痘治疗原则：治疗方法包括支持措施、抗病毒治疗、水痘带状疱疹免疫球蛋白 (VZIG) 给药和继发性细菌感染的管理。隔离水痘患者，因为该病传染性强，可发生空气传播。详细诊疗、用药内容扫描二维码即可免费看丘疹性荨麻疹丘疹性荨麻疹是一种夏季常见的疾病。临床表现：表现为对蚊子、跳蚤、臭虫和其他昆虫的叮咬产生过敏反应而引起慢性或反复性丘疹。单个丘疹可能围绕着「红色风团」，且其顶端显示有小水疱 。图 5. 颈部和左上胸部多发性红色丘疹 [2] 图 6. 上肢风团样丘疹和斑块 [2]治疗原则：丘疹性荨麻疹的治疗为保守性治疗。可局部使用温和的类固醇和全身使用抗组胺药物来缓解瘙痒。在某些情况下，丘疹性荨麻疹可能严重到需要全身短期使用皮质类固醇激素。请注意，当患者在室外使用驱蚊剂，或当患者正在治疗丘疹性荨麻疹时，有必要对室内宠物身上的跳蚤和蜱虫进行控制。详细诊疗、用药内容扫描二维码即可免费看光线性唇炎光线性唇炎由长期紫外线暴露引发。临床表现：临床表现多样，常见体征包括唇红苍白、脱屑、慢性糜烂和溃疡、白色斑块、唇红缘与皮肤之间界限模糊，唇红萎缩，红斑等。触诊病损表面可有砂纸样感觉。光化性唇炎的唇红角化斑块可增厚、硬化、结节化，甚至快速生长，最终形成一个或多个溃疡，引起出血和疼痛，出现此类症状时往往提示病损有癌变趋势。图 7. 光化性痒疹：唇炎 [1]治疗原则：消除患者所处环境中的致病刺激物，是治疗刺激性唇炎的主要方式。外用皮质类固醇有助于减轻炎症和瘙痒。详细诊疗、用药内容扫描二维码即可免费看| 蜱虫叮咬（莱姆病）完整诊疗、用药内容▼点击「阅读原文」或「扫描下方二维码」即可免费看策划：圆脸大侠，瓜叽呀编辑：瓜叽呀题图：站酷海洛投稿：drugs@dxy.cn参考文献：[1] Nahhas AF, Oberlin DM, Braunberger TL,et al. Recent Developments in the Diagnosis and Management of Photosensitive Disorders. Am J Clin Dermatol, 2018, 19(5):707-731.[2] Leung AKC, Barankin B, Leong KF. Pruritic erythematous papules in a previously well teenager. Paediatr Child Health, 2018, 23(2):119-121.