Contact Dermatitis Glossary of Medical Terms

Allergen: A substance that is foreign to the body and can cause an allergic reaction in certain people. For examples, pollen, dander, mold.
See the entire definition of Allergen

Allergic contact dermatitis: A red, itchy, weepy reaction where the skin has come into contact with a substance that the immune system recognizes as foreign, such as poison ivy , poison oak or poison sumac or certain preservatives in creams and lotions. This type of reaction reflects a specific sensitivity or allergy to a specific substance. Also called allergic contact eczema.
See the entire definition of Allergic contact dermatitis

Allergic reaction: The hypersensitive response of the immune system of an allergic individual to a substance.
See the entire definition of Allergic reaction

Allergy : A misguided reaction to foreign substances by the immune system , the body system of defense against foreign invaders, particularly pathogens (the agents of infection ). The allergic reaction is misguided in that these foreign substances are usually harmless. The substances that trigger allergy are called allergen. Examples include pollens , dust mite, molds , danders , and certain foods. People prone to allergies are said to be allergic or atopic .
See the entire definition of Allergy

Antibody: An immunoglobulin, a specialized immune protein , produced because of the introduction of an antigen into the body, and which possesses the remarkable ability to combine with the very antigen that triggered its production.
See the entire definition of Antibody

Antihistamines: Drugs that combat the histamine released during an allergic reaction by blocking the action of the histamine on the tissue. Antihistamines do not stop the formation of histamine nor do they stop the conflict between the IgE and antigen. Therefore, antihistamines do not stop the allergic reaction but protect tissues from some of its effects. Antihistamines frequently cause mouth dryness and sleepiness. Newer "non sedating" antihistamines are generally thought to be somewhat less effective. Antihistamine side effects that very occasionally occur include urine retention in males and fast heart rate.
See the entire definition of Antihistamines

Asthma : A common disorder in which chronic inflammation of the bronchial tubes (bronchi) makes them swell, narrowing the airways. Asthma involves only the bronchial tubes and does not affect the air sacs ( alveoli ) or the lung tissue (the parenchyma of the lung) itself.
See the entire definition of Asthma

Blister: A collection of fluid underneath the top layer of skin (epidermis). One that is more than 5 mm in diameter with thin walls and is full of watery fluid is called a bulla or a bleb. There are many causes of blisters including burns , vesicant agents, friction forces, and diseases of the skin.
See the entire definition of Blister

Blood: The familiar red fluid in the body that contains white and red blood cells , platelets , proteins , and other elements. The blood is transported throughout the body by the circulatory system . Blood functions in two directions: arterial and venous. Arterial blood is the means by which oxygen and nutrients are transported to tissues while venous blood is the means by which carbon dioxide and metabolic by-products are transported to the lungs and kidneys, respectively, for removal from the body.
See the entire definition of Blood

Calamine: An astringent made from zinc carbonate or zinc oxide, usually used in lotion form to treat skin problems that cause itching or discomfort.
See the entire definition of Calamine

CDC: The Centers for Disease Control and Prevention , the US agency charged with tracking and investigating public health trends. The stated mission of the CDC is "To promote health and quality of life by preventing and controlling disease, injury, and disability." The CDC is a part of the U.S. Public Health Services (PHS) under the Department of Health and Human Services (HHS).
See the entire definition of CDC

Chronic: This important term in medicine comes from the Greek chronos, time and means lasting a long time.
See the entire definition of Chronic

Condition: The term "condition" has a number of biomedical meanings including the following:

1. An unhealthy state, such as in "this is a progressive condition."
2. A state of fitness, such as "getting into condition."
3. Something that is essential to the occurrence of something else; essentially a "precondition."
4. As a verb: to cause a change in something so that a response that was previously associated with a certain stimulus becomes associated with another stimulus; to condition a person, as in behavioral conditioning.

See the entire definition of Condition

Contact dermatitis: A skin condition caused by contact between skin and some substance. Includes irritant contact dermatitis (a rash brought on purely by repeated irritation from a substance such as water causing "dish pan hands") and allergic contact dermatitis (involving a specific sensitivity or allergy to a specific substance such as poison ivy ).
See the entire definition of Contact dermatitis

Corticosteroid: Any of the steroid hormones made by the cortex (outer layer) of the adrenal gland. Cortisol is a corticosteroid.
See the entire definition of Corticosteroid

Dermatitis: Inflammation of the skin, either due to direct contact with an irritating substance, or to an allergic reaction. Symptoms of dermatitis include redness, itching, and in some cases blistering.
See the entire definition of Dermatitis

Eczema: A particular type of inflammatory reaction of the skin in which there are typically vesicles (tiny blister-like raised areas) in the first stage followed by erythema (reddening), edema (swelling), papules (bumps), and crusting of the skin followed, finally, by lichenification (thickening) and scaling of the skin. Eczema characteristically causes itching and burning of the skin.
See the entire definition of Eczema

Emergency department: The department of a hospital responsible for the provision of medical and surgical care to patients arriving at the hospital in need of immediate care. Emergency department personnel may also respond to certain situations within the hospital such cardiac arrests.
See the entire definition of Emergency department

Histamine: Substance that plays a major role in many allergic reactions. Histamine dilates blood vessels and makes the vessel walls abnormally permeable.
See the entire definition of Histamine

Hives: A raised, itchy area of skin that is usually a sign of an allergic reaction. It can be rounded or flat-topped but is always elevated above the surrounding skin. It reflects circumscribed dermal edema (local swelling of the skin). The hives are usually well circumscribed but may be coalescent and will blanch with pressure. They typically last less than 4 hours but they may stay for days or weeks. Approximately 20% of the population has experienced a bout of hives.
See the entire definition of Hives

Hospital: It may seem unnecessary to define a "hospital" since everyone knows the nature of a hospital. A hospital began as a charitable institution for the needy, aged, infirm, or young.
See the entire definition of Hospital

Immune: Protected against infection. The Latin immunis means free, exempt.
See the entire definition of Immune

Immune system: A complex system that is responsible for distinguishing us from everything foreign to us, and for protecting us against infections and foreign substances. The immune system works to seek and kill invaders.
See the entire definition of Immune system

Immunoglobulin: A protein produced by plasma cells and lymphocytes and characteristic of these types of cells. Immunoglobulins play an essential role in the body's immune system. They attach to foreign substances, such as bacteria, and assist in destroying them. Immunoglobulin is abbreviated Ig. The classes of immunoglobulins are termed immunoglobulin A (IgA), immunoglobulin G (IgG), immunoglobulin M (IgM), immunoglobulin D (IgD) and immunoglobulin E (IgE).
See the entire definition of Immunoglobulin

Immunoglobulin E: Abbreviated IgE. A class of immunoglobulins that includes the antibodies elicited by an allergic substance (allergen). A person who has an allergy usually has elevated blood levels of IgE. IgE antibodies attack and engage the invading army of allergens.
See the entire definition of Immunoglobulin E

Immunology: The study of all aspects of the immune system including its structure and function, disorders of the immune system, blood banking, immunization and organ transplantation.
See the entire definition of Immunology

Inflammation: A basic way in which the body reacts to infection , irritation or other injury, the key feature being redness, warmth, swelling and pain . Inflammation is now recognized as a type of nonspecific immune response .
See the entire definition of Inflammation

Irritant contact dermatitis : A rash brought about by constant irritation from a substance. For example, anyone who washes their hands many times a day can develop "dish pan hands." Another example is in young children who lick their lips repeatedly, resulting in an irritant reaction to saliva.
See the entire definition of Irritant contact dermatitis

Itching: An uncomfortable sensation in the skin that feels as if something is crawling on the skin or in the skin, and makes the person want to scratch the affected area.
See the entire definition of Itching

Medication: 1. A drug or medicine. 2. The administration of a drug or medicine. (Note that "medication" does not have the dangerous double meaning of "drug.")
See the entire definition of Medication

Nickel: A silver-white metallic element. Long-term exposure to nickel, such as from jewelry, can cause a form of contact dermatitis called nickel dermatitis. Exposure to nickel fumes can cause nasal cancer and lung cancer .
See the entire definition of Nickel

Ointment: A medication preparation that is applied topically (onto the skin). An ointment has an oil base whereas a cream is water-soluble. (The word ointment comes from the Latin ungere meaning anoint with oil).
See the entire definition of Ointment

Pharmacy: A location where prescription drugs are sold. A pharmacy is, by law, constantly supervised by a licensed pharmacist.
See the entire definition of Pharmacy

Poison: Any substance that can cause severe distress or death if ingested, breathed in, or absorbed through the skin. Many substances that normally cause no problems, including water and most vitamins , can be poisonous if taken in too large of a quantity. Poison treatment depends on the substance: if there are treatment instructions on the substance's container and you are sure it contained no other item, follow those directions immediately. Always contact your nearest Poison Control Center if you are concerned about possible poison ingestion.
See the entire definition of Poison

Poison ivy : Skin inflammation resulting from contact with oils from the poison ivy vine. Chemicals produced by this vine cause an immune reaction, producing redness, itching, and blistering of the skin.
See the entire definition of Poison ivy

Poison oak: Poison oak is a form of "contact dermatitis" or inflammation of the skin resulting from chemicals produced from the poison oak plant contacting the skin. The chemicals cause an immune reaction producing redness, itching and blistering of the skin.
See the entire definition of Poison oak

Prescription: A physician's order for the preparation and administration of a drug or device for a patient. A prescription has several parts. They include the superscription or heading with the symbol "R" or "Rx", which stands for the word recipe (meaning, in Latin, to take); the inscription, which contains the names and quantities of the ingredients; the subscription or directions for compounding the drug; and the signature which is often preceded by the sign "s" standing for signa (Latin for mark), giving the directions to be marked on the container.
See the entire definition of Prescription

Protein: A large molecule composed of one or more chains of amino acids in a specific order determined by the base sequence of nucleotides in the DNA coding for the protein.
See the entire definition of Protein

Rash : Breaking out (eruption) of the skin. Medically, a rash is referred to as an exanthem.
See the entire definition of Rash

Skin: The skin is the body's outer covering. It protects us against heat and light, injury, and infection. It regulates body temperature and stores water, fat, and vitamin D. Weighing about 6 pounds, the skin is the body's largest organ. It is made up of two main layers; the outer epidermis and the inner dermis.

See the entire definition of Skin

Steroid: A general class of chemical substances that are structurally related to one another and share the same chemical skeleton (a tetracyclic cyclopenta[a]phenanthrene skeleton).
See the entire definition of Steroid

Substance: 1. Material with particular features, as a pressor substance .
2. The material that makes up an organ or structure. Also known in medicine as the substantia.
3. A psychoactive drug as, for example, in substance abuse .
See the entire definition of Substance

Trigger: Something that either sets off a disease in people who are genetically predisposed to developing the disease, or that causes a certain symptom to occur in a person who has a disease. For example, sunlight can trigger rashes in people with lupus .
See the entire definition of Trigger

Most Popular Topics

Explore 80+ Centers

Search Medical Dictionary

or A-Z List

We subscribe to the HONcode principles. Verify here.

©2008 WebMD, Inc. All rights reserved.
eMedicineHealth does not provide medical advice, diagnosis or treatment. See Additional Information.