Lupus Glossary of Terms and Definitions

It is sometimes difficult and overwhelming to make sense of all of the medical terminology involved in navigating through a lupus diagnosis and the potential overlap diseases that may accompany it over time. We have created this lupus glossary to help define some of the terms that you may come across in your readings, research, and doctor visits. We will keep adding to this list as we create more blogs and content so that you always will have the opportunity to learn even more about the condition/disease with which you are dealing. Knowledge is power, right?




The medical term for all types of hair loss. Alopecia most commonly refers to hair loss on the head, but can be anywhere on the body. Hair loss can be localized in patches, or diffuse, which is seen as hair thinning. Alopecia is typically divided into two types: scarring (cicatricial) alopecia, where inflammation destroys the hair follicle leading to permanent hair loss, and non-scarring alopecia.


Antibodies are the immune system’s first line of defense: the molecules that detect and attack invaders. In autoimmune diseases like lupus, antibodies mistakenly attack a patient’s own tissue and organs.


A foreign substance that provokes an immune system response when introduced to the body. Almost any large molecule can be an antigen– including elements of bacteria, viruses, protozoa, food, and various cells and tissues.


Antimalarial medications are used to prevent and treat malaria, and are also prescribed for lupus and rheumatoid arthritis (although there is no known link between malaria and lupus or rheumatoid arthritis). These medicines work by reducing inflammation, and often reduce overall disease activity. They may also reduce flares, and protect internal organs such as the kidneys. Using them often will allow patients with lupus to decrease the dosage of their other medications that may have more severe side effects. Common anti-malarial medications are hydroxychloroquine (Plaquenil) and choloquine (Aralen).

Antinuclear Antibodies

Antinuclear antibodies (ANAs) are specific antibodies that attack cell nuclei. Most people have ANAs, but the presence of large amounts of them may indicate an autoimmune disease. The ANA test is a test that measures pattern and amount of ANAs. While an ANA test alone can’t confirm a diagnosis, people with lupus, scleroderma, Sjögren’s syndrome, Raynaud’s disease, rheumatoid arthritis, and autoimmune hepatitis often have a positive test for antinuclear antibodies. More than 95 percent of people with lupus test positive.

Autoimmune Disease/ Autoimmune Disorder

An illness that occurs when the body tissues are attacked by its own immune system. The immune system is a complex organization within the body that is designed normally to “seek and destroy” invaders of the body, including infectious agents. Patients with autoimmune diseases frequently have unusual antibodies circulating in their blood that target their own body tissues. Back to A, Back to Top


Butterfly Rash 

A flat reddish facial rash that spreads over the cheeks and bridge of the nose, resembling the outstretched wings of a butterfly. The rash is usually painless and does not itch. Much like other symptoms of lupus, it can worsen with exposure to sunlight. About half of people with lupus experience some form of this characteristic rash, however it can also occur in other conditions such as rosacea and seborrheic dermatitis. Back to B, Back to Top


Chronic Cutaneous Lupus (CCLE)

Chronic cutaneous lupus (CCLE) is one of three types of cutaneous lupus erythematosus, which is the general skin-related lupus. The most common form of CCLE is discoid lupus, a skin condition characterized by inflamed red disc-like patches, coming together to form a rash that can have a scaling or crusty appearance. Discoid lupus typically occurs on the face, neck, and scalp, and can affect all ages and ethnic groups.

Chronic Diseases/ Illnesses

Diseases that are long-lasting, noncommunicable (non-infectious and noncontagious), and can be managed but are rarely cured. Although chronic diseases are more common among older adults, they affect people of all ages. While chronic illnesses are some of the most common and costly health problems, they are also some of the most preventable, and with proper care they can almost always be effectively controlled.

Clinical trial

A research study that directly involves a particular person or group of people. Clinical trials are one type of clinical research that follow a pre-defined plan, and seek to answer specific questions about biomedical or behavioral interventions (drugs, treatments, devices, or new ways of using them). Ultimately, they will determine whether interventions are safe and effective. By taking part in clinical trials, participants can not only play a more active role in their own health care, but they can also access new treatments and help others by contributing to medical research.


The main supportive protein of connective tissue. Collagen is a fibrous protein that makes up about 30% of the protein content of our body, and contributes to our tissues’ ability to withstand stretching.

Connective Tissue

The “cellular glue” that supports and binds your tissues. Connective tissue gives your tissues their shape, helps keep them strong, and many times allows them to carry out their functions. Examples of specialized connective tissue are bone, cartilage, blood, and fat.

Connective Tissue Disease

Connective tissue disease (CTD) is actually a  large category of diseases that primarily target the body’s connective tissue. Many CTDs involve abnormal immune system activity, and are associated with a combination of systemic autoimmune diseases.


Corticosteroids are drugs that closely resemble cortisol, the body’s primary stress hormone. Cortisol is produced in the adrenal glands when the body experiences stress. It’s primary effect is metabolic: it influences how fast we convert glucose (sugar) from our bloodstream into energy. This produces an immediate boost of energy when the body feels threatened. Cortisol also decreases inflammation and immune response, which comes in handy for lupus patients. As a treatment for lupus, corticosteroids work by decreasing inflammation while reducing immune system activity in order to minimize tissue damage. This can be invaluable in situations where severe or chronic inflammation threatens internal organs.

CRP (C-Reactive Protein)

A blood protein produced in the liver that corresponds to inflammation. CRP usually appears after an injury, infection, or inflammation, and then disappears once the inflammation goes away. High levels of CRP may indicate infection, or a chronic inflammatory disease like lupus.

Cutaneous Lupus Erythematosus (CLE)

The skin-related form of lupus, an autoimmune disease where the body’s immune system begins to attack it’s own healthy tissue. When lupus is found throughout the body’s internal organs, it is called Systemic Lupus Erythematosus (SLE). CLE refers to lupus as it affects the skin, and can occur with or without the systemic form of the disease. There are three types of CLE: chronic cutaneous lupus (CCLE), subacute cutaneous lupus (SCLE) and acute cutaneous lupus (ACLE). They each exhibit characteristic skin reactions, ranging from a butterfly facial rash, to ring-shaped red patches with lighter centers, to scaly red plaques that can lead to scarring, pigmentation changes, and skin thinning. All three are aggravated by exposure to sunlight, with or without the presence of a rash. Back to C, Back to Top



A chronic inflammatory disease that affects skin and muscle. The characteristic symptoms are muscle weakness, and a distinctive skin rash. Dermatomyositis is an autoimmune disease where the immune system mistakenly attacks healthy cells in muscles and skin. The most characteristic mark of dermatomyositis is a patchy, scaly, dark red (even violet) rash on the face, neck, shoulders, upper chest, knees, or back. This rash many times appears before any other symptoms.

Discoid Lupus

Discoid lupus is the most common form of chronic cutaneous lupus, the skin-affecting form of lupus. It is characterized by red, inflamed, scaly, discoid (circular) patches that usually do not itch. This rash usually appears on sun-exposed areas, and worsens (or is triggered by) sun exposure. Discoid lupus most commonly affects the scalp, face, and neck. Although the majority of cases are found in women (like other forms of lupus), discoid lupus affects all ages and ethnic groups. If left untreated, discoid lupus can lead to scarring, skin thinning, and permanent hair loss. However early diagnosis, treatment, and preventative care greatly improve outcomes.

Discoid Rash

Red, thick, raised or flat circular patches on the skin with well-defined borders. The defining characteristic of discoid lupus.

Drug-Induced Lupus

Drug-induced lupus (DIL) is a temporary autoimmune disorder resembling lupus that develops as a reaction to medication. As with lupus, in DIL the body’s immune system mistakenly attacks healthy tissue. This results in inflammation, and may affect the joints, heart, and lungs. Both the symptoms and treatment for DIL are very similar to the treatment for SLE, the systemic form of lupus. Over 38 medications have been identified to have some risk of causing DIL, with the three most common being Hydralazine (Apresoline), Procainamide (Pronestyl), and Quinidine (Quinaglute). DIL is different from typical short-term side effects of medications, as short-term side effects will usually occur within hours or days of starting regular use of a medication. DIL only appears after daily, long-term use of a medication (at least 3-6 months, more typically after a year). DIL will usually disappear within a couple weeks of stopping use of the medication causing it, although it may take longer. Back to D, Back to Top



The branch of medical science concerned with all of the factors that determine health-related conditions or events (including diseases). Epidemiological research helps us understand how health problems are changing and affect our society and economy.


The cause of a disease or condition. Also the study or investigation the cause for something, usually in a historical or mythological sense. Back to E, Back to Top.



A disorder characterized by widespread pain, aches, stiffness, abnormal pain processing, sleep disturbance, fatigue, and many times problems with thinking, memory (“fibro fog”), and psychological distress. Women are much more likely to develop fibromyalgia than men, and while there is no cure, medications can be used to manage symptoms.

Flares (as in lupus flares)

A flare is a period of time when symptoms recur or become more severe, and can be triggered by a number of things. Triggers can include UV light, an infection, stress, pregnancy or changes in medication.

Function of B-cells and T-cells

B-cells and T-cells work together.  When a T-cell recognizes an antigen, it will produce chemicals known as cytokines that cause B-cells to multiply and release many immune proteins (antibodies).  Circulating widely in the bloodstream, antibodies recognize foreign particles and trigger inflammation to help the body rid itself of the virus or bacteria. B-cells and T-cells play a vital role in protecting the immune system. Back to F, Back to Top


Immune Complex

Immune complex occurs when an antibody binds to an antigen, a toxin, microorganism, or protein that is foreign to the body. Immune complex molecules help fight disease—but in lupus, individuals form autoantibodies that attack the person’s own tissue and organs.


An agent that can suppress or prevent an immune response. Immunosuppressants typically refer to a category of medications that are used to prevent rejection of organ transplants, and to treat autoimmune diseases, including rheumatoid arthritis, Crohn’s disease, and lupus. Some treatments for other diseases (including cancer) may act as immunosuppressants in addition to accomplishing their primary task.


An inflammatory response (inflammation) occurs when tissues are injured by bacteria, trauma, toxins, heat, or any other cause. The damaged cells release chemicals including histamine, bradykinin, and prostaglandins. These chemicals cause blood vessels to leak fluid into the tissues, causing swelling. This helps isolate the foreign substance from further contact with body tissues.


Interferons (IFNs) are proteins made and released by host cells in response to the presence of pathogens such as viruses, bacteria, parasites or tumor cells. They allow for communication between cells to trigger the protective defenses of the immune system that eradicate pathogens or tumors.

Intravenous (IV) Infusion

Intravenous infusion or IV infusion is a medical term that describes the way certain kinds of medicines or other substances, such as nutrition, are delivered to the body.  This method is often used when the substance cannot be taken orally.  Sometimes the therapy must bypass the gut or go directly into the veins. Many therapies are delivered via IV infusion—including intravenous steroids and chemotherapeutic agents for people with lupus. Back to I, Back to Top



An injury or wound. Also an abnormal structural change in a part or organ resulting from injury or disease.


Lupus is one of many disorders of the immune system known as autoimmune diseases. In autoimmune diseases, the immune system turns against parts of the body it is designed to protect. This leads to inflammation and damage to various body tissues. Lupus can affect many parts of the body, including the joints, skin, kidneys, heart, lungs, blood vessels, and brain. Although people with the disease may have many different symptoms, some of the most common ones include extreme fatigue, painful or swollen joints (arthritis), unexplained fever, skin rashes, and kidney problems. Back to L, Back to Top


Mixed Connective Tissue Disease (MCTD)

An autoimmune disorder that causes overlapping features of three connective tissue disorders: lupus, scleroderma, and polymyositis. MCTD may also have features of rheumatoid arthritis. This condition is most often diagnosed in women in their 20’s and 30’s. Occasionally, children are affected. At this time the cause of this condition is unknown. Back to M, Back to Top


Neonatal Lupus

Neonatal lupus is a rare condition – about 1 to 2 percent of babies born to mothers who have autoimmune disease or carry the antibodies will develop neonatal lupus.  The disease is presumed to be the result of these antibodies crossing the placenta in pregnancy from mother to her developing baby. Neonatal lupus is usually benign and the signs — such as skin rash, liver problems, and low blood cell counts —are generally short lived.  Symptoms usually disappear within months after birth, when infants begin to develop their own immune system — and, the mother’s antibodies leave the baby’s body.


Lupus nephritis is kidney inflammation caused by systemic lupus erythematosus (SLE or lupus). SLE is an autoimmune disease—a disorder in which the body’s immune system attacks the body’s own cells and organs. Up to 60 percent of people with SLE are diagnosed with lupus nephritis, which can lead to significant illness and even death.


Nephrologists are internists who specialize in treating patients with kidney disease.

Neurologic Disorders

Diseases of the brain, spinal cord and nerves throughout your body. Together they control all the workings of the body. When something goes wrong with a part of your nervous system, you can have trouble moving, speaking, swallowing, breathing or learning. You can also have problems with your memory, senses or mood.


A disease or condition of the nervous system; nerve damage.

Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)

The muscle and joint pain associated with lupus—as well as other chronic conditions where inflammation is present—are most often treated with non-steroidal anti-inflammatory drugs (NSAIDs).  Examples of over-the-counter NSAIDs are aspirin and ibuprofen. Back to N, Back to Top



As opposed to rheumatoid arthritis which is a chronic inflammatory condition and autoimmune disorder that generally affects the lining of the joints in your hands and feet. Rheumatoid arthritis creates a painful swelling that can eventually lead to deformity and erosion of your joints and bones, osteoarthritis is a wearing and tearing of your joints where the protective cartilage on the ends of your bones wears down over time.

Overlap Disease

Some lupus (SLE) patients have been told by one physician that they have lupus, while told by another physician that they have, for example, scleroderma or another related disorder.  How and why does this happen?  Although lupus most often occurs alone, many people with lupus can also have symptoms characteristic of one or more of the other connective tissue diseases. When this occurs, a physician may use the term “overlap” to describe the illness. People affected with lupus may have none, one, or several of these well-recognized overlaps. These overlaps are, typically connective tissue diseases, or closely related group of disorders that affect the connective tissues of the body. Back to O, Back to Top



The science and branch of medicine that pursues the cause, origin, and nature of disease.


Photosensitivity is an abnormal reaction to sunlight.

Pleural Effusion

A pleural effusion is a buildup of fluid between the layers of tissue that line the lungs and chest cavity. Your body produces pleural fluid in small amounts to lubricate the surfaces of the pleura, the thin tissue that lines the chest cavity and surrounds the lungs. A pleural effusion is an abnormal, excessive collection of this fluid.


Inflammation of the pleura, the membrane that surrounds and safeguards the lungs. This inflammation usually occurs when an infection or toxin irritates the surface of the pleura. This causes sharp chest pains, the primary symptom of pleurisy.


A persistent inflammatory muscle disease that occurs when white blood cells (the cells of inflammation) invade muscles, especially essential skeletal muscles in the torso. Polymyositis results in muscle pain, tenderness, and weakness. It is a systemic disease, meaning it affects the whole body. It is a chronic condition where the body experiences progressive muscle weakness, interspersed with flares (periods of heightened symptoms), and remissions (periods of minimal or no symptoms). Treatment usually entails high doses of corticosteroids (i.e. prednisone), and potentially immunosuppresants (i.e. methotrezate, cyclophosphamide).

Proliferative Lupus Nephritis

The term for severe stages of lupus nephritis — or inflammation of the kidneys due to lupus – is proliferative lupus nephritis.  Lupus nephritis is a serious condition, which occurs when autoantibodies affect the filtering structure of the kidneys.  Proliferative lupus nephritis may lead to blood or protein in the urine, impaired kidney function, or even kidney failure. At any stage of lupus nephritis, early diagnosis and treatment can greatly improve outcomes.


Also called albuminuria or urine albumin- proteinuria is a condition in which urine contains an abnormal amount of protein. Albumin is the main protein in the blood. Proteins are the building blocks for all body parts, including muscles, bones, hair, and nails. Proteins in the blood also perform a number of important functions. They protect the body from infection, help blood clot, and keep the right amount of fluid circulating throughout the body. Proteinuria is a sign of chronic kidney disease (CKD). If CKD progresses, it can lead to end-stage renal disease (ESRD), when the kidneys fail completely. A person with ESRD must receive a kidney transplant or regular blood-cleansing treatments called dialysis.

Pulmonary Function Test

A group of non-invasive tests that measure lung function, allowing your doctor to follow your lung condition over time. This can help track lung involvement with SLE, pinpoint the cause of shortness of breath and other lung symptoms, and assess lung damage or recovery. Back to P, Back to Top


Raynaud’s Phenomenon

Raynaud’s phenomenon is a rare disorder that affects the arteries. Arteries are blood vessels that carry blood from your heart to different parts of your body. Raynaud’s sometimes is called a disease, syndrome, or phenomenon. The disorder is marked by brief episodes of vasospasm (VA-so-spazm), which is a narrowing of the blood vessels. Vasospasm of the arteries reduces blood flow to the fingers and toes. In people who have Raynaud’s, the disorder usually affects the fingers. In about 40 percent of people who have Raynaud’s, it affects the toes. Rarely, the disorder affects the nose, ears, nipples, and lips.

Renal Disorder

Renal disorder, or nephropathy, means damage to or disease of a kidney. Nephrosis is non-inflammatory nephropathy. Nephritis is inflammatory kidney disease.


Rheumatism or rheumatic disorder is a non-specific term for medical problems affecting the joints and connective tissue. The study of, and therapeutic interventions in, such disorders is called rheumatology.


The role of the rheumatologist is to diagnose (detect), treat and medically manage patients with arthritis and other rheumatic diseases. These health problems affect the joints, muscles, bones and sometimes other internal organs (e.g., kidneys, lungs, blood vessels, brain). Because these diseases are often complex, they benefit from the care of an expert. Only rheumatologists are experts in this field of medicine.

Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a form of arthritis that causes pain, swelling, stiffness and loss of function in your joints. It can affect any joint but is common in the wrist and fingers. You might have the disease for only a short time, or symptoms might come and go. The severe form can last a lifetime. Rheumatoid arthritis is different from osteoarthritis, the common arthritis that often comes with older age. RA can affect body parts besides joints, such as your eyes, mouth and lungs. No one knows what causes rheumatoid arthritis. Genes, environment and hormones might contribute. Treatments include medicine, lifestyle changes and surgery. Back to R, Back to Top



A connective tissue disease that involves changes in the skin, blood vessels, muscles, and internal organs. It is a type of autoimmune disorder, a condition that occurs when the immune system mistakenly attacks and destroys healthy body tissue.The cause of scleroderma is unknown. People with this condition have a buildup of a substance called collagen in the skin and other organs. This buildup leads to the symptoms of the disease. The disease usually affects people 30 to 50 years old. Women get scleroderma more often than men do. Widespread scleroderma can occur with other autoimmune diseases, including systemic lupus erythematosus and polymyositis. In such cases, the disorder is referred to as mixed connective disease.

Sjogren’s syndrome

Sjogren’s syndrome is a disease that causes dryness in your mouth and eyes. It can also lead to dryness in other places that need moisture, such as your nose, throat and skin. Most people who get Sjogren’s syndrome are older than 40. Nine out of 10 are women. Sjogren’s syndrome is sometimes linked to rheumatic problems such as rheumatoid arthritis. In Sjogren’s syndrome, your immune system attacks the glands that make tears and saliva. It may also affect your joints, lungs, kidneys, blood vessels, digestive organs and nerves. The main symptoms are dry eyes and dry mouth.  Treatment focuses on relieving symptoms.


Steroids is the shortened term for corticosteroids, a drug commonly used to reduce inflammation in lupus.  The term steroids is not to be confused with the male hormone-related steroid compounds designed to enhance athletic performance.

Sub-acute Cutaneous Lupus Erythematosus (SCLE)

Sub-acute cutaneous lupus (SCLE) is one of three subsets of the general lupus skin disorder called cutaneous lupus erythematosus. Characterized by lesions that appear on parts of the body that are exposed to sun, SCLE makes up approximately 10 percent of lupus cases.  Lesions from SCLE do not cause permanent scarring.


Systemic refers to something that is spread throughout, system-wide, affecting a group or system such as a body, economy, market or society as a whole. Systemic Lupus Erythematosus (SLE) Systemic lupus erythematosus (SLE) is an autoimmune disease in which the body’s immune system mistakenly attacks healthy tissue. It can affect the skin, joints, kidneys, brain, and other organs, and leads to long-term (chronic) inflammation. The underlying cause of autoimmune diseases is not fully known. SLE is much more common in women than men. It may occur at any age, but appears most often in people between the ages of 10 and 50. African Americans and Asians are affected more often than people from other races. Back to S, Back to Top



T-cells are a type of blood cell that belong to a group of white blood cells (WBCs) called lymphocytes, which help the body fight infection.  T cells play a major role in protecting the immune system by identifying, directly attacking, and destroying infectious agents. The function of B cells and T cells is vital to the immune system, allowing humans to ward off and better cope with often-hostile bacteria, viruses, and other foreign matter. Back to T, Back to Top



An open sore (break in the skin or mucous membrane that is not healing), accompanied by disintegration of tissue, and many times pus.

Undifferentiated Connective Tissue Diseases 

The term undifferentiated connective tissue diseases is used to define conditions characterized by the presence of signs and symptoms suggestive of a systemic autoimmune disease that do not satisfy the criteria for defined connective tissue diseases (CTD) such as systemic lupus erythematosus (SLE), Sjögren’s syndrome (SS), rheumatoid arthritis (RA) and others. A small percentage of patients presenting with an undifferentiated profile will develop during the first year follow up of a full blown CTD, however an average of 75% will maintain an undifferentiated clinical course. These patients may be defined as having a stable undifferentiated connective tissue diseases (UCTD). The most characteristic symptoms of UCTD are represented by arthritis and arthralgias, Raynaud’s phenomenon, leukopenia, while neurological and kidney involvement are virtually absent. Eighty percent of these patients have a single autoantibody specificity, more frequently anti-Ro and anti-RNP antibodies. Stable UCTD are considered as distinct clinical entities and therefore it has been proposed to define those conditions as UCTD. Back to U, Back to Top



Vasculitis is a condition that involves inflammation in the blood vessels. The condition occurs if your immune system attacks your blood vessels by mistake. This may happen as the result of an infection, a medicine, or another disease or condition. Vasculitis can affect any of the body’s blood vessels. These include arteries, veins, and capillaries. Arteries carry blood from your heart to your body’s organs. Veins carry blood from your organs and limbs back to your heart. Capillaries connect the small arteries and veins. Back to V, Back to Top


Still unsure about a definition?  Have additional words to suggest?  Please email [email protected] with your suggestions and questions!