The term “plaque” describes an abnormal, localized buildup or deposit distinct from the surrounding tissue. This single word represents two profoundly different pathologies depending on its location. Large plaque refers either to deposits found within the inner lining of blood vessels, which carry systemic consequences, or to raised patches on the skin, which are primarily localized dermatological concerns. The composition, formation process, and risk profiles of arterial plaque and skin plaque are fundamentally different. Recognizing this duality is key to understanding the specific health challenge an individual may face.
Formation and Risk of Arterial Plaque
Arterial plaque is the hallmark of atherosclerosis, a progressive condition developing over many years. This buildup begins as a response to injury within the artery wall, often caused by high blood pressure, elevated cholesterol, or inflammation. The initial damage attracts immune cells, allowing low-density lipoprotein (LDL) cholesterol to penetrate the vessel wall where it is ingested by macrophages, forming foam cells.
The growing deposit, known as an atheroma, is comprised of fatty substances, cholesterol, cellular waste, and calcium. This accumulation gradually thickens the artery wall and poses two primary dangers. The first is stenosis, a gradual narrowing that restricts the flow of oxygen-rich blood to tissues. This restricted flow can cause pain, such as angina or claudication, and is a common feature of coronary artery disease or peripheral artery disease.
The second, and often more abrupt, danger is the rupture of the plaque’s fibrous cap. Certain types, particularly low-density, non-calcified plaques, are vulnerable to rupture. When a vulnerable plaque ruptures, its inner contents are exposed to the bloodstream, triggering the rapid formation of a blood clot (thrombus).
This sudden clot can completely block blood flow. If this occurs in a coronary artery, it results in a myocardial infarction (heart attack), or an ischemic stroke if it occurs in an artery leading to the brain. The severity of the risk depends not solely on the size of the plaque but also on its composition and stability.
Types and Characteristics of Skin Plaque
In dermatology, a plaque is defined as a raised, solid, flat-topped lesion greater than one centimeter in diameter. This differentiates it from smaller raised lesions, known as papules. Skin plaques are caused by an abnormal thickening of the epidermis, or by an accumulation of inflammatory cells or metabolic deposits in the deeper layers.
One common example is the plaque seen in psoriasis, which presents as dry, well-defined, raised, red patches covered with a characteristic silvery, white scale. This scaling results from the rapid and excessive turnover of skin cells, which accumulate on the surface in days instead of the normal month-long cycle.
Another instance is actinic keratosis, which appears as rough, scaly patches on sun-exposed skin and is considered a precancerous lesion.
Skin plaques can also be a feature of other inflammatory conditions, such as certain forms of eczema. While often noticeable and sometimes accompanied by discomfort like itching or burning, dermatological plaques represent a localized problem. The primary concern is typically related to chronic inflammation, localized pain, or the potential for malignant transformation, such as with untreated actinic keratosis.
Systemic Conditions That Affect Both Arteries and Skin
Despite their distinct locations, large plaque in both the arteries and on the skin can signal underlying systemic disorders that share common pathological pathways. Chronic systemic inflammation is a significant biological link connecting certain skin conditions to cardiovascular risk. For example, severe plaque psoriasis is associated with an increased risk of developing or accelerating atherosclerosis.
The inflammatory state driving psoriatic plaque formation is not confined to the skin; it involves the release of inflammatory molecules that circulate throughout the body. These mediators contribute to the development of plaque within the arterial walls, accelerating the atherosclerotic process. The visible skin disease thus acts as a signpost for a hidden, potentially more harmful, disease in the arteries.
Another systemic connection is found in disorders of lipid metabolism, known as dyslipidemia. Uncontrolled high levels of cholesterol and triglycerides fuel arterial plaque formation and can also manifest as distinct skin deposits called xanthomas. Xanthomas are yellowish papules, nodules, or plaques resulting from the accumulation of lipid-filled immune cells (macrophages) in the skin and sometimes the underlying tendons.
The presence of xanthomas, often found on the eyelids or elbows, is a physical sign that the body is struggling to process lipids effectively. This is the same metabolic failure that drives arterial plaque formation. Identifying xanthomas can therefore be an early, visible indicator of a severe lipid disorder promoting dangerous plaque buildup in the arteries.
Medical Evaluation and Initial Management Steps
The medical evaluation of large plaque differs significantly depending on whether the concern is arterial or dermatological. For arterial plaque, the diagnostic process focuses on assessing the location, size, and stability of the deposits within the vessels. Non-invasive tools like Doppler sonography (ultrasound) are used to measure blood flow and estimate the degree of narrowing in arteries, such as the carotid arteries.
Advanced imaging, including computed tomography (CT) scans, provides detailed images to quantify the volume and composition of coronary artery plaque, particularly the amount of calcium present. Blood testing, specifically a lipid panel, is routinely used to measure circulating fats like LDL cholesterol and triglycerides, which are the fundamental building blocks of arterial plaque.
In contrast, the evaluation of skin plaque begins with a thorough visual inspection by a dermatologist, assessing the lesion’s size, color, texture, and borders. If the clinical appearance is atypical or malignancy is suspected, a skin biopsy is often performed. This procedure removes a small sample of the lesion using punch or shave techniques for laboratory analysis, providing a definitive diagnosis of the underlying skin condition.
Initial management for both conditions begins with broad steps centered on general health improvement. These include adopting dietary changes to reduce saturated fats and cholesterol, increasing physical activity, and stopping smoking. Consulting with a specialist—a cardiologist for arterial plaque or a dermatologist for skin plaque—is necessary to establish an accurate diagnosis and create a targeted, long-term management plan.