Hypersensitivity in the context of Modafinil

A disease is a particular abnormal condition that adversely affects the structure or function of all or part of an organism and is not immediately due to any external injury. Diseases are often known to be medical conditions that are associated with specific signs and symptoms. A disease may be caused by external factors such as pathogens or by internal dysfunctions. For example, internal dysfunctions of the immune system can produce a variety of different diseases, including various forms of immunodeficiency, hypersensitivity, allergies, and autoimmune disorders.

In humans, disease is often used more broadly to refer to any condition that causes pain, dysfunction, distress, social problems, or death to the person affected, or similar problems for those in contact with the person. In this broader sense, it sometimes includes injuries, disabilities, disorders, syndromes, infections, isolated symptoms, deviant behaviors, and atypical variations of structure and function, while in other contexts and for other purposes these may be considered distinguishable categories. Diseases can affect people not only physically but also mentally, as contracting and living with a disease can alter the affected person's perspective on life.

An immune response is a physiological reaction which occurs within an organism in the context of inflammation for the purpose of defending against exogenous factors. These include a wide variety of different toxins, viruses, intra- and extracellular bacteria, protozoa, helminths, and fungi which could cause serious problems to the health of the host organism if not cleared from the body.

In addition, there are other forms of immune response. For example, harmless exogenous factors (such as pollen and food components) can trigger allergy; latex and metals are also known allergens.A transplanted tissue (for example, blood) or organ can cause graft-versus-host disease. A type of immune reactivity known as Rh disease can be observed in pregnant women. These special forms of immune response are classified as hypersensitivity. Another special form of immune response is antitumor immunity.

Immunology is a branch of biology and medicine that covers the study of immune systems in all organisms.

Immunology charts, measures, and contextualizes the physiological functioning of the immune system in states of both health and diseases; malfunctions of the immune system in immunological disorders (such as autoimmune diseases, hypersensitivities, immune deficiency, and transplant rejection); and the physical, chemical, and physiological characteristics of the components of the immune system in vitro, in situ, and in vivo. Immunology has applications in numerous disciplines of medicine, particularly in the fields of organ transplantation, oncology, rheumatology, virology, bacteriology, parasitology, psychiatry, and dermatology.

Dermatitis is a term used for different types of skin inflammation, typically characterized by itchiness, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become thickened. The area of skin involved can vary from small to covering the entire body. Dermatitis is also called eczema but the same term is often used for the most common type of skin inflammation, atopic dermatitis.

The exact cause of the condition is often unclear. Cases may involve a combination of allergy and poor venous return. The type of dermatitis is generally determined by the person's history and the location of the rash. For example, irritant dermatitis often occurs on the hands of those who frequently get them wet. Allergic contact dermatitis occurs upon exposure to an allergen, causing a hypersensitivity reaction in the skin.

Premedication is using medication before some other therapy (usually surgery or chemotherapy) to prepare for that forthcoming therapy. Typical examples include premedicating with a sedative or analgesic before surgery; using prophylactic (preventive) antibiotics before surgery; and using antiemetics or antihistamines before chemotherapy.

Premedication before chemotherapy for cancer often consists of drug regimens (usually 2 or more drugs, e.g. dexamethasone, diphenhydramine and omeprazole) given to a patient minutes to hours before the chemotherapy to avert side effects or hypersensitivity reactions (i.e. allergic reactions).

Heartburn is a burning sensation felt behind the breastbone. It is a symptom that is commonly linked to acid reflux and is often triggered by food. Lying down, bending, lifting, and performing certain exercises can exacerbate heartburn. Causes include acid reflux, gastroesophageal reflux disease (GERD), damage to the esophageal lining, bile acid, mechanical stimulation to the esophagus, and esophageal hypersensitivity. Heartburn affects 25% of the population at least once a month.

Endoscopy and esophageal pH monitoring can be used to evaluate heartburn. Some causes of heartburn, such as GERD, may be diagnosed based on symptoms alone. Potential differential diagnoses for heartburn include motility disorders, ulcers, inflammation of the esophagus, and medication side effects. Lifestyle changes, such as losing weight and avoiding fatty foods, can improve heartburn. Over-the-counter alginates or antacids can help with mild or occasional heartburn. Heartburn treatment primarily involves antisecretory medications like H2 receptor antagonists (H2RAs) and proton-pump inhibitors (PPIs).

Type I hypersensitivity (or immediate hypersensitivity), in the Gell and Coombs classification of allergic reactions, is an allergic reaction provoked by re-exposure to a specific type of antigen referred to as an allergen. Type I is distinct from type II, type III and type IV hypersensitivities. The relevance of the Gell and Coombs classification of allergic reactions has been questioned in the modern-day understanding of allergy, and it has limited utility in clinical practice.

Exposure may be by ingestion, inhalation, injection, or direct contact.

Atopy is the tendency to produce an exaggerated immunoglobulin E (IgE) immune response to otherwise harmless substances in the environment. Allergic diseases are clinical manifestations of such inappropriate, atopic responses.

Atopy may have a hereditary component, although contact with the allergen or irritant must occur before the hypersensitivity reaction can develop (characteristically after re-exposure). Maternal psychological trauma during pregnancy may also be a strong indicator for development of atopy.

Dermatitis is a term used for different types of skin inflammation, typically characterized by itchiness, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become thickened. The area of skin involved can vary from small to covering the entire body. Dermatitis is also called eczema, but "eczema" is often used for the most common type of skin inflammation, atopic dermatitis.

The exact cause of the condition is often unclear. Cases may involve a combination of allergy and poor venous return. The type of dermatitis is generally determined by the person's history and the location of the rash. For example, irritant dermatitis often occurs on the hands of those who frequently get them wet. Allergic contact dermatitis occurs upon exposure to an allergen, causing a hypersensitivity reaction in the skin.

Serum sickness in humans is a reaction to proteins in antiserum derived from a non-human animal source, occurring an average of 8 days after exposure. Symptoms often include a rash, joint pain, fever, and lymphadenopathy. It is a type of hypersensitivity, specifically immune complex hypersensitivity (type III). The term serum sickness–like reaction (SSLR) is occasionally used to refer to similar illnesses that arise from the introduction of certain non-protein substances, such as penicillin.

Serum sickness may be diagnosed based on the symptoms, and using a blood test and a urine test. It may be prevented by not using an antitoxin derived from animal serum, and through prophylactic antihistamines or corticosteroids. It usually resolves naturally, but may be treated with corticosteroids, antihistamines, analgesics, and (in severe cases) prednisone. It was first characterized in 1906.

Hyperalgesia (/ˌhaɪpərælˈdʒiːziə/ or /-siə/; hyper from Greek ὑπέρ (huper) 'over' + -algesia from Greek ἄλγος (algos) 'pain') is an abnormally increased sensitivity to pain, which may be caused by damage to nociceptors or peripheral nerves and can cause hypersensitivity to stimulus. Prostaglandins E and F are largely responsible for sensitizing the nociceptors. Temporary increased sensitivity to pain also occurs as part of sickness behavior, the evolved response to infection.