nih-gov/medlineplus.gov/ency/article/004014.htm
2025-02-26 13:17:41 -05:00

280 lines
No EOL
31 KiB
HTML
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

<!DOCTYPE html>
<html lang="en" id="article" class="nojs us" data-root="//medlineplus.gov" itemid="https://medlineplus.gov/ency/article/004014.htm" itemtype="http://schema.org/MedicalWebPage" itemscope="">
<head>
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1"/>
<meta http-equiv="window-target" content="_top"/>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
<meta charset="utf-8"/>
<meta property="fb:app_id" content="1042245625821448"/>
<meta name="expires" content="Wed, 05 02 2025"/>
<meta name="ac-dictionary" content="medlineplus-ac-dictionary"/>
<link rel="shortcut icon" href="https://medlineplus.gov/images/favicon.ico" type="image/x-icon"/>
<link rel="apple-touch-icon" href="//medlineplus.gov/images/touch-icon.png"/>
<meta name="viewport" content="width=device-width, initial-scale=1"/>
<link rel="stylesheet" href="https://medlineplus.gov/css/common_new.css?04272023"/>
<!--[if IE 8]> <link rel="stylesheet" href="https://medlineplus.gov/css/ie8/common.css"><![endif]-->
<link rel="stylesheet" href="https://medlineplus.gov/uswds/css/uswds_styles.css"/>
<link rel="stylesheet" href="https://medlineplus.gov/css/ency/ency2.css?07162024"/>
<script type="text/javascript">document.querySelector("html").className = document.querySelector("html").className.replace(/nojs[\s]*/g, '');</script>
<script src="https://medlineplus.gov/uswds/js/uswds-init.min.js" type="text/javascript">
</script>
<script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&amp;l='+l:'';j.async=true;j.src='//www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-MMVM77');</script>
<link rel="canonical" href="https://medlineplus.gov/ency/article/004014.htm" itemprop="url"/>
<link rel="alternative" hreflang="es" href="https://medlineplus.gov/spanish/ency/article/004014.htm"/>
<link rel="alternative" hreflang="en" href="https://medlineplus.gov/ency/article/004014.htm"/><meta property="og:title" content="Aging changes in skin: MedlinePlus Medical Encyclopedia"/><meta property="og:url" content="https://medlineplus.gov/ency/article/004014.htm"/><meta property="twitter:title" content="Aging changes in skin: MedlinePlus Medical Encyclopedia"/><meta name="twitter:card" content="summary_large_image"/><meta name="description" content="Aging changes in the skin are a group of common conditions and developments that occur as people grow older."/><meta itemprop="description" name="description" content="Aging changes in the skin are a group of common conditions and developments that occur as people grow older."/><meta property="og:description" content="Aging changes in the skin are a group of common conditions and developments that occur as people grow older."/><meta property="twitter:description" content="Aging changes in the skin are a group of common conditions and developments that occur as people grow older."/><meta property="og:image" content="https://medlineplus.gov/images/share_ency_1.jpg"/><meta property="og:image" content="https://medlineplus.gov/images/share_ency_2.jpg"/><meta property="og:image" content="https://medlineplus.gov/images/share_ency_3.jpg"/><meta property="twitter:image" content="https://medlineplus.gov/images/share_ency_1.jpg"/>
<title>Aging changes in skin: MedlinePlus Medical Encyclopedia</title>
</head>
<body><link href="http://schema.org/Patient" itemprop="audience"/>
<!-- Google Tag Manager -->
<noscript><iframe title="googletagmanager" src="//www.googletagmanager.com/ns.html?id=GTM-MMVM77" height="0" width="0" style="display:none;visibility:hidden">
</iframe>
</noscript>
<!-- End Google Tag Manager -->
<a name="top" id="top">
</a>
<a class="hide-offscreen" href="#start">Skip navigation</a>
<section class="usa-banner" aria-label="Official website of the United States government">
<div class="usa-accordion">
<header class="usa-banner__header">
<div class="usa-banner__inner">
<div class="grid-col-auto">
<img aria-hidden="true" class="usa-banner__header-flag" src="https://medlineplus.gov/uswds/img/us_flag_small.png" alt=""/>
</div>
<div class="grid-col-fill tablet:grid-col-auto" aria-hidden="true">
<p class="usa-banner__header-text">
An official website of the United States government
</p>
<p class="usa-banner__header-action">Heres how you know</p>
</div>
<button type="button" class="usa-accordion__button usa-banner__button" aria-expanded="false" aria-controls="gov-banner-default-default">
<span class="usa-banner__button-text">Heres how you know</span>
</button>
</div>
</header>
<div class="usa-banner__content usa-accordion__content" id="gov-banner-default-default">
<div class="grid-row grid-gap-lg">
<div class="usa-banner__guidance tablet:grid-col-6">
<img class="usa-banner__icon usa-media-block__img" src="https://medlineplus.gov/uswds/img/icon-dot-gov.svg" role="img" alt="" aria-hidden="true"/>
<div class="usa-media-block__body">
<p>
<strong>Official websites use .gov</strong><br/>A
<strong>.gov</strong> website belongs to an official government
organization in the United States.
</p>
</div>
</div>
<div class="usa-banner__guidance tablet:grid-col-6">
<img class="usa-banner__icon usa-media-block__img" src="https://medlineplus.gov/uswds/img/icon-https.svg" role="img" alt="" aria-hidden="true"/>
<div class="usa-media-block__body">
<p>
<strong>Secure .gov websites use HTTPS</strong><br/>A
<strong>lock</strong> (
<span class="icon-lock"><svg xmlns="http://www.w3.org/2000/svg" width="52" height="64" viewBox="0 0 52 64" class="usa-banner__lock-image" role="img" aria-labelledby="banner-lock-description-default" focusable="false">
<title id="banner-lock-title-default">Lock</title>
<desc id="banner-lock-description-default">Locked padlock icon</desc>
<path fill="#000000" fill-rule="evenodd" d="M26 0c10.493 0 19 8.507 19 19v9h3a4 4 0 0 1 4 4v28a4 4 0 0 1-4 4H4a4 4 0 0 1-4-4V32a4 4 0 0 1 4-4h3v-9C7 8.507 15.507 0 26 0zm0 8c-5.979 0-10.843 4.77-10.996 10.712L15 19v9h22v-9c0-6.075-4.925-11-11-11z">
</path>
</svg> </span>) or <strong>https://</strong> means youve safely connected to
the .gov website. Share sensitive information only on official,
secure websites.
</p>
</div>
</div>
</div>
</div>
</div>
</section>
<div id="mplus-wrap">
<header>
<div id="mplus-header">
<!-- Orgs
================================================== -->
<div id="mplus-orgs">
<a title="National Institutes of Health" target="_blank" class="nih-org" href="//www.nih.gov/">
<img alt="National Institutes of Health" src="https://medlineplus.gov/images/nihlogo.png" class="nihlogo"/>
</a><a target="_blank" href="https://www.nlm.nih.gov/"> National Library of Medicine </a>
</div>
<!-- Logo
================================================== -->
<div id="mplus-logo" class="years-25">
<a href="https://medlineplus.gov">
<img src="https://medlineplus.gov/images/m_logo_25.png" title="MedlinePlus Trusted Health Information for You" alt="MedlinePlus Trusted Health Information for You"/>
</a>
</div>
<!-- Nav Menu
================================================== -->
<div id="mplus-nav">
<div class="sm-live-area hide-offscreen" aria-live="polite">The navigation menu has been collapsed.</div>
<!-- Menu Button-->
<button type="submit" aria-controls="mplus-menu-list" role="button" title="Menu" class="navmenu-btn" id="sm-menu-btn" aria-pressed="false" tabindex="0">Menu<span class="icon icon-nav-menu">
</span></button><ul class="nav-list" id="mplus-menu-list">
<li><a href="https://medlineplus.gov/healthtopics.html">Health Topics</a></li>
<li><a href="https://medlineplus.gov/druginformation.html">Drugs &amp; Supplements</a></li>
<li><a href="https://medlineplus.gov/genetics/">Genetics</a></li>
<li><a href="https://medlineplus.gov/lab-tests/">Medical Tests</a></li>
<li><a href="https://medlineplus.gov/encyclopedia.html">Medical Encyclopedia</a></li>
<li><a href="https://medlineplus.gov/about/">About MedlinePlus</a></li>
</ul><button type="submit" aria-controls="mplus-search" role="button" title="Search" class="navmenu-btn" id="sm-search-btn" aria-pressed="false" tabindex="0"><span class="hide-offscreen">Show </span>Search<span class="icon icon-nav-search">
</span></button>
<div class="top-1">
<!-- Search
================================================== -->
<form target="_self" title="Search MedlinePlus" action="//vsearch.nlm.nih.gov/vivisimo/cgi-bin/query-meta" method="get" id="mplus-search">
<input type="hidden" value="medlineplus" name="v:project"/>
<input type="hidden" value="medlineplus-bundle" name="v:sources"/>
<div class="form-box text-combo">
<div class="form-area"><label for="searchtext_primary" class="hide-offscreen">Search MedlinePlus</label>
<span role="status" aria-live="polite" class="ui-helper-hidden-accessible">
</span><input type="text" aria-haspopup="true" aria-autocomplete="list" role="textbox" autocomplete="off" name="query" size="40" maxlength="400" title="Site Search input" alt="Site Search input" placeholder="Search MedlinePlus" class="form-text ui-autocomplete-input" id="searchtext_primary"/>
</div>
<div class="button-area">
<button type="submit" alt="Search MedlinePlus" title="Search MedlinePlus" class="form-btn">GO</button>
</div>
</div>
</form>
<!-- Secondary Nav
================================================== -->
<div class="secondarynav">
<ul class="nav-list">
<li><a href="https://medlineplus.gov/about/"><span>About MedlinePlus</span></a></li>
<li><a href="https://medlineplus.gov/whatsnew/"><span>What's New</span></a></li>
<li><a href="https://medlineplus.gov/sitemap.html"><span>Site Map</span></a></li>
<li><a target="_blank" href="https://support.nlm.nih.gov/knowledgebase/category/?id=CAT-01231&amp;category=medlineplus&amp;from=//medlineplus.gov/ency/article/004014.htm"><span>Customer Support</span></a></li>
</ul>
</div>
</div>
<!-- Nav Bar
================================================== -->
<div id="mplus-nav-bar">
<ul class="nav-list">
<li><a href="https://medlineplus.gov/healthtopics.html">Health Topics</a></li><li><a href="https://medlineplus.gov/druginformation.html">Drugs &amp; Supplements</a></li><li><a href="https://medlineplus.gov/genetics/">Genetics</a></li><li><a href="https://medlineplus.gov/lab-tests/">Medical Tests</a></li><li><a href="https://medlineplus.gov/encyclopedia.html">Medical Encyclopedia</a></li>
</ul>
</div>
<a title="Español" id="mplus-lang-toggle" href="../../spanish/ency/article/004014.htm">Español</a>
</div>
</div>
</header>
<!-- Content
================================================== -->
<div id="mplus-content">
<!-- Breadrcumbs -->
<div id="breadcrumbs"><div itemtype="http://schema.org/BreadcrumbList" itemscope="" itemprop="breadcrumb"><span class="hide-offscreen">You Are Here:</span>
<div itemscope itemprop="itemListElement" itemtype="http://schema.org/ListItem">
<a href="https://medlineplus.gov" itemprop="item"><span itemprop="name">Home</span></a>
&rarr;
<meta itemprop="position" content="1"/>
</div>
<div itemscope itemprop="itemListElement" itemtype="http://schema.org/ListItem">
<a href="https://medlineplus.gov/encyclopedia.html" itemprop="item"><span itemprop="name">Medical Encyclopedia</span></a>
&rarr;
<meta itemprop="position" content="2"/>
</div>
</div><div><span>Aging changes in skin</span></div></div>
<span class="page-url print-only">URL of this page: //medlineplus.gov/ency/article/004014.htm
</span>
<!-- Article -->
<article><div id="d-article"><div class="page-info"><div class="page-title"><a name="start" id="start">
</a><h1 class="with-also" itemprop="name">Aging changes in skin</h1>
</div><div class="page-actions">
</div>
<noscript>
<span class="js-disabled-message">To use the sharing features on this page, please enable JavaScript.</span>
</noscript></div><div class="main"><div id="ency_summary"><p>Aging changes in the skin are a group of common conditions and developments that occur as people grow older.</p></div><section><div class="section"><div class="section-header"><div class="section-title"><h2>Information</h2></div><div class="section-button"><button type="submit" aria-controls="section-1" role="button" title="Expand/Collapse section"><span class="icon icon-section-action">
</span></button></div><div class="sm-live-area hide-offscreen" aria-live="polite">
</div></div><div class="section-body" id="section-1"><p>Skin changes are among the most visible signs of aging. Evidence of increasing age includes <a test="test" href="./003252.htm">wrinkles</a> and sagging skin. Whitening or graying of the hair is another obvious sign of aging.</p><p>Your skin does many things. It: </p><ul><li>Contains nerve receptors that allow you to feel touch, pain, and pressure</li><li>Helps control fluid and <a test="test" href="./002350.htm">electrolyte</a> balance</li><li>Helps control your body temperature</li><li>Protects you from the environment </li></ul><p>Although skin has many layers, it can generally be divided into three main parts:</p><ul><li>The outer part (epidermis) contains skin cells, pigment, and proteins.</li><li>The middle part (dermis) contains skin cells, blood vessels, nerves, hair follicles, and oil glands. The dermis provides nutrients to the epidermis.</li><li>The inner layer under the dermis (the <a test="test" href="./002297.htm">subcutaneous</a> layer) contains sweat glands, some hair follicles, blood vessels, and fat. </li></ul><p>Each layer also contains connective tissue with collagen fibers to give support and elastin fibers to provide flexibility and strength.</p><div class="videobox"><div class="group"><img class="rollover_globals" alt="Components of skin" title="Components of skin" src="//medlineplus.gov/ency/images/ency/tnails/200098t.gif"/>Watch this video about:<a class="blk" href="../anatomyvideos/000029.htm">Components of skin</a></div></div><p>Skin changes are related to environmental factors, genetic makeup, nutrition, and other factors. The greatest single factor, though, is sun exposure. You can see this by comparing areas of your body that have regular sun exposure with areas that are protected from sunlight.</p><p>Natural pigments seem to provide some protection against sun-induced skin damage. Blue-eyed, fair-skinned people show more aging skin changes than people with darker, more heavily pigmented skin.</p><p>AGING CHANGES</p><p>With aging, the outer skin layer (epidermis) thins, even though the number of cell layers remains unchanged.</p><p>The number of pigment-containing cells (melanocytes) decreases. The remaining melanocytes increase in size. Aging skin looks thinner, paler, and clear (translucent). Pigmented spots including <a test="test" href="./001141.htm">age spots</a> or "liver spots" may appear in sun-exposed areas. The medical term for these areas is lentigos.</p><p>Changes in the connective tissue reduce the skin's strength and elasticity. This is known as elastosis. It is more noticeable in sun-exposed areas (solar elastosis). Elastosis produces the leathery, weather-beaten appearance common to farmers, sailors, and others who spend a large amount of time outdoors.</p><p>The blood vessels of the dermis become more fragile. This leads to bruising, bleeding under the skin (often called senile purpura), and <a test="test" href="./001441.htm">cherry angiomas</a>.</p><p>Sebaceous glands produce less oil as you age. Men experience a minimal decrease, most often after the age of 80. Women gradually produce less oil beginning after menopause. This can make it harder to keep the skin moist, resulting in dryness and itchiness.</p><p>The subcutaneous fat layer thins so it has less insulation and padding. This increases your risk of skin injury and reduces your ability to maintain body temperature. Because you have less natural insulation, you can get <a test="test" href="./000038.htm">hypothermia</a> in cold weather.</p><p>Some medicines are absorbed by the fat layer. Shrinkage of this layer may change the way that these medicines work.</p><p>The sweat glands produce less sweat. This makes it harder to keep cool. Your risk for overheating or developing <a test="test" href="./000056.htm">heat stroke</a> increases.</p><p>Growths such as <a test="test" href="./000848.htm">skin tags</a>, <a test="test" href="./000885.htm">warts</a>, brown rough patches (seborrheic keratoses), and other blemishes are more common in older people. Also common are pinkish rough patches (actinic keratosis) which have a small chance of becoming a skin cancer. Skin cancers are also common and usually located in sun-exposed areas.</p><p>EFFECT OF CHANGES</p><p>As you age, you are at increased risk for skin injury. Your skin is thinner, more fragile, and you lose some of the protective fat layer. You also may be less able to sense touch, pressure, vibration, heat, and cold. </p><p>Rubbing or pulling on the skin can cause skin tears. Fragile blood vessels can break easily. Bruises, flat collections of blood (purpura), and raised collections of blood (<a test="test" href="./003235.htm">hematomas</a>) may form after even a minor injury.</p><p>Pressure ulcers can be caused by skin changes, loss of the fat layer, reduced activity, poor nutrition, and illnesses. Sores are most easily seen on the outside surface of the forearms, but they can occur anywhere on the body. </p><p>Aging skin repairs itself more slowly than younger skin. Wound healing may be up to 4 times slower. This contributes to pressure ulcers and infections. <a test="test" href="./001214.htm">Diabetes</a>, blood vessel changes, lowered immunity, and other factors also affect healing.</p><p>COMMON PROBLEMS</p><p>Skin disorders are so common among older people that it is often hard to tell normal changes from those related to a disorder. More than 90% of all older people have some type of skin disorder.</p><p>Skin disorders can be caused by many conditions, including:</p><ul><li>Blood vessel diseases, such as <a test="test" href="./000171.htm">atherosclerosis</a></li><li>Diabetes</li><li><a test="test" href="./007115.htm">Heart disease</a></li><li><a test="test" href="./000205.htm">Liver disease</a></li><li>Nutritional deficiencies</li><li>Obesity</li><li>Reactions to medicines</li><li>Stress </li></ul><p>Other causes of skin changes:</p><ul><li>Allergies to plants and other substances</li><li>Climate</li><li>Clothing</li><li>Exposures to industrial and household chemicals</li><li>Indoor heating </li></ul><p>Sunlight can cause:</p><ul><li>Loss of elasticity (elastosis)</li><li>Noncancerous skin growths (keratoacanthomas)</li><li>Pigment changes such as liver spots</li><li>Thickening of the skin </li></ul><p>Sun exposure has also been directly linked to skin cancers, including basal cell cancer, squamous cell carcinoma, and melanoma.</p><p>PREVENTION</p><p>Because most skin changes are related to sun exposure, prevention is a lifelong process.</p><ul><li>Prevent sunburn if at all possible.</li><li>Use a good quality sunscreen when outdoors, even in the winter.</li><li>Wear protective clothing and a hat when needed. </li></ul><p>Good nutrition and adequate fluids are also helpful. <a test="test" href="./000982.htm">Dehydration</a> increases the risk of skin injury. Sometimes minor nutritional deficiencies can cause rashes, <a test="test" href="./003220.htm">skin lesions</a>, and other skin changes, even if you have no other symptoms.</p><p>Keep skin moist with lotions and other moisturizers. . Do not use soaps that are strongly detergent (drying) or heavily perfumed. Bath oils are not recommended because they can cause you to slip and fall. Moist skin is more comfortable and will heal more quickly.</p><p>RELATED TOPICS</p><ul><li><a test="test" href="./003998.htm">Aging changes in body shape</a></li><li><a test="test" href="./004005.htm">Aging changes in hair and nails</a></li><li><a test="test" href="./004000.htm">Aging changes in hormone production</a></li><li><a test="test" href="./004012.htm">Aging changes in organs, tissues, and cells</a></li><li><a test="test" href="./004015.htm">Aging changes in the bones, muscles, and joints</a></li><li><a test="test" href="./003999.htm">Aging changes in the breast</a></li><li><a test="test" href="./004004.htm">Aging changes in the face</a></li><li><a test="test" href="./004013.htm">Aging changes in the senses</a></li></ul></div></div></section><section><div class="section"><div class="section-header"><div class="section-title"><h2>Alternative Names</h2></div><div class="section-button"><button type="submit" aria-controls="section-Alt" role="button" title="Expand/Collapse section"><span class="icon icon-section-action">
</span></button></div><div class="sm-live-area hide-offscreen" aria-live="polite">
</div></div><div class="section-body" id="section-Alt"><p>Wrinkles - aging changes; Thinning of skin</p></div></div></section><section><div class="section sec-mb"><div class="section-header"><div class="section-title"><h2>Images</h2></div><div class="section-button"><button type="submit" aria-controls="section-tnails" role="button" title="Expand/Collapse section"><span class="icon icon-section-action">
</span></button></div><div class="sm-live-area hide-offscreen" aria-live="polite">
</div></div><div name="Images" class="section-body" id="section-tnails"><ul class="img-grid group">
<li><img src="//medlineplus.gov/ency/images/ency/tnails/8691t.jpg" alt="Changes in face with age" title="Changes in face with age" class="side-img"/><a href="../imagepages/8691.htm">Changes in face with age</a></li>
</ul></div></div></section><section><div class="section"><div class="section-header"><div class="section-title"><h2>References</h2></div><div class="section-button"><button type="submit" aria-controls="section-Ref" role="button" title="Expand/Collapse section"><span class="icon icon-section-action">
</span></button></div><div class="sm-live-area hide-offscreen" aria-live="polite">
</div></div><div class="section-body" id="section-Ref"><p>Standring S. Skin and its appendages. In: Standring S, ed. <em>Gray's Anatomy</em>. 42nd ed. Philadelphia, PA: Elsevier; 2021:chap 7.</p><p>Tobin DJ, Veysey EC, Finlay AY. Aging and the skin. In: Fillit HM, Rockwood K, Young J, eds. <em>Brocklehurst's Textbook of Geriatric Medicine and Gerontology</em>. 8th ed. Philadelphia, PA: Elsevier; 2017:chap 25.</p><p>Walston JD. Common clinical sequelae of aging. In: Goldman L, Schafer AI, eds. <em>Goldman-Cecil Medicine</em>. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 22.</p></div></div></section>
<section><div class="section"><div class="section-header"><div class="section-title"><h2>Review Date 7/21/2022</h2></div><div class="section-button"><button type="submit" aria-controls="section-version" role="button" title="Expand/Collapse section"><span class="icon icon-section-action">
</span></button></div><div class="sm-live-area hide-offscreen" aria-live="polite">
</div></div>
<div id="section-version" class="section-body"><p>Updated by: Frank D. Brodkey, MD, FCCM, Associate Professor, Section of Pulmonary and Critical Care Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.</p>
</div></div></section><section><div class="section ency-citation"><div class="section-header"><div class="section-title ency-citation"><div id="citation-how-to"><button><span>Learn how to cite this page</span></button></div></div><div class="sm-live-area hide-offscreen" aria-live="polite">
</div></div></div></section><section><div class="section sec-mb"><div class="section-header"><div class="section-title"><h2>Related MedlinePlus Health Topics</h2></div><div class="section-button"><button type="submit" aria-controls="section-mtp" role="button" title="Expand/Collapse section"><span class="icon icon-section-action">
</span></button></div><div class="sm-live-area hide-offscreen" aria-live="polite">
</div></div><div name="Related MedlinePlus Health Topics" class="section-body" id="section-mtp"><ul class="side-nav"><li><a href="https://medlineplus.gov/olderadulthealth.html">Older Adult Health</a></li>
<li><a href="https://medlineplus.gov/skinaging.html">Skin Aging</a></li>
</ul></div></div></section></div></div></article>
</div>
<footer>
<div class="provider-box group">
<div class="urac-logo">
<a href="https://accreditnet.urac.org/directory/#/certification/HCP-2/info"><img src="https://medlineplus.gov/images/CertifiedSeal.png"/></a>
<p class="urac-logo-info">Health Content Provider<br>06/01/2025</p>
</div>
<p class="adam-info">
<a href='javascript:urac_open();'>A.D.A.M., Inc. is accredited by URAC</a>, for Health Content Provider (www.urac.org). URAC's <a href='javascript:hwsopen();'>accreditation program</a> is an independent audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s <a href='javascript:edpolopen();'>editorial policy, editorial process</a>, and <a href='javascript:ppopen();'>privacy policy</a>. A.D.A.M. is also a founding member of Hi-Ethics. This site complies with the HONcode standard for trustworthy health information: <a href='javascript:honc_open();'>verify here</a>.
</p>
</div>
<p class="adam-info">
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only they do not constitute endorsements of those other sites. No warranty of any kind, either expressed or implied, is made as to the accuracy, reliability, timeliness, or correctness of any translations made by a third-party service of the information provided herein into any other language. © 1997-2025 A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
</p>
<div class="adam-logo">
<a href="https://www.adam.com/about" target="_blank"><img width="49" height="10" alt="About A.D.A.M." src="https://medlineplus.gov/ency/images/ency/ftrAdamlogo.gif"/></a>
</div>
<div id="mplus-footer">
<div class="footer1">
<ul class="secondarynav">
<li><a href="https://medlineplus.gov/about/">About MedlinePlus</a></li>
<li><a href="https://medlineplus.gov/whatsnew/">What's New</a></li>
<li><a href="https://medlineplus.gov/sitemap.html">Site Map</a></li>
<li><a name="contact" target="_blank" href="https://support.nlm.nih.gov/knowledgebase/category/?id=CAT-01231&amp;category=medlineplus&amp;from="><span>Customer Support</span></a></li>
</ul>
<ul class="follow-footer">
<li><a href="https://medlineplus.gov/rss.html" class="follow-item">Subscribe to RSS<img src="https://medlineplus.gov/images/feed.png" class="social-media-toolkit-icon" alt="RSS" title="RSS"></a></li>
<li><span class="follow-label">Follow us</span>
<a href="https://twitter.com/medlineplus" class="follow-item" target="_blank"><img src="https://medlineplus.gov/images/i_share_twitter.png" class="follow-icon" alt="X" title="X"></a>
<a href="https://facebook.com/Mplus.gov/" class="follow-item" target="_blank"><img src="https://medlineplus.gov/images/i_share_fb.png" class="follow-icon" alt="Facebook" title="Facebook"></a>
<a href="https://www.instagram.com/mplusgov/" class="follow-item" target="_blank"><img src="https://medlineplus.gov/images/Instagram_Glyph_Gradient_RGB.png" class="follow-icon" alt="Instagram" title="Instagram"></a>
</li>
<li><a href="https://medlineplus.gov/social-media-toolkit/" class="social-media-toolkit-item">Social Media Toolkit<img src="https://medlineplus.gov/images/i_social_media_toolkit.png" class="social-media-toolkit-icon" alt="Social Media Toolkit" title="Social Media Toolkit"></a></li>
</ul>
</div>
<div class="footer2">
<ul>
<li><a href="https://www.nlm.nih.gov/web_policies.html" target="_blank">NLM Web Policies</a></li>
<li><a href="https://medlineplus.gov/about/using/usingcontent/" >Copyright</a></li>
<li><a href="//medlineplus.gov/accessibility.html">Accessibility</a></li>
<li><a href="https://medlineplus.gov/about/using/criteria/">Guidelines for Links</a></li>
<li><a href="//medlineplus.gov/plugins.html">Viewers &amp; Players</a></li>
<li><a href="https://www.hhs.gov/vulnerability-disclosure-policy/index.html" target="_blank">HHS Vulnerability Disclosure</a></li>
<li><a href="https://medlineplus.gov/medlineplus-connect/">MedlinePlus Connect for EHRs</a></li>
<li><a href="https://medlineplus.gov/about/developers/">For Developers</a></li>
</ul>
<div class="address">
<a href="//www.nlm.nih.gov" target="_blank">National Library of Medicine</a>
<span>8600 Rockville Pike, Bethesda, MD 20894</span>
<a href="//www.hhs.gov" target="_blank">U.S. Department of Health and Human Services</a>
<a href="//www.nih.gov" target="_blank">National Institutes of Health</a>
</div>
<div class="return-top"><a href="#top" title="Return to top"><img class="return-top-icon" alt="Return to top" src="https://medlineplus.gov/images/return-top.png"></a></div>
</div>
</div>
</footer>
</div><!-- End Wrap -->
<script src="https://medlineplus.gov/jslib/jquery-3.6.0.min.js" type="text/javascript">
</script>
<script src="https://medlineplus.gov/jslib/mplus-frontend-controls.js" type="text/javascript">
</script>
<!--[if lte IE 9]>
<script src="https://medlineplus.gov/jslib/jquery.placeholder.js" type="text/javascript"></script>
<![endif]-->
<script src="https://medlineplus.gov/jslib/mplus-share.js?id=1112022" type="text/javascript">
</script>
<script src="https://medlineplus.gov/jslib/control.js" type="text/javascript">
</script>
<script src="https://medlineplus.gov/uswds/js/uswds.min.js" type="text/javascript">
</script>
<script src="https://medlineplus.gov/jslib/ency/ency.js" type="text/javascript">
</script>
</body>
</html>