Drug eruption

In medicine, a drug eruption is an adverse drug reaction of the skin. Most drug-induced cutaneous reactions are mild and disappear when the offending drug is withdrawn. These are called 'simple' drug eruptions. However, more serious drug eruptions may be associated with organ injury such as liver or kidney damage and are categorized as 'complex'. Drugs can also cause hair and nail changes, affect the mucous membranes, or cause itching without outward skin changes.basophil surface receptorsangioedemacomplement driven cell lysishemolytic anemia, Goodpasture's, ANCA vasculitisin tissues-triggers recruitment of leukocytesinflammation leading to tissue destructionUS AfricanThai, EuropeanMalaysian, KoreanHLA-B*1502Han In medicine, a drug eruption is an adverse drug reaction of the skin. Most drug-induced cutaneous reactions are mild and disappear when the offending drug is withdrawn. These are called 'simple' drug eruptions. However, more serious drug eruptions may be associated with organ injury such as liver or kidney damage and are categorized as 'complex'. Drugs can also cause hair and nail changes, affect the mucous membranes, or cause itching without outward skin changes. The use of synthetic pharmaceuticals and biopharmaceuticals in medicine has revolutionized human health, allowing us to live longer lives. As a consequence, the average human adult is exposed to a large number of drugs over longer treatment periods throughout a lifetime. This unprecedented rise in pharmaceutical use has led to an increasing number of observed adverse drug reactions. There are two broad categories of adverse drug reactions. Type A reactions are known side effects of a drug that are largely predictable and are called, pharmatoxicologic. Whereas Type B or hypersensitivity reactions, are often immune-mediated and reproducible with repeated exposure to normal dosages of a given drug. Unlike type A reactions, the mechanism of type B or hypersensitivity drug reactions is not fully elucidated. However, there is a complex interplay between a patient's inherited genetics, the pharmacotoxicology of the drug and the immune response that ultimately give rise to the manifestation of a drug eruption. Because the manifestation of a drug eruption is complex and highly individual, there are many subfields in medicine that are studying this phenomenon. For example, the field of pharmacogenomics aims to prevent the occurrence of severe adverse drug reactions by analyzing a person's inherited genetic risk. As such, there are clinical examples of inherited genetic alleles that are known to predict drug hypersensitivities and for which diagnostic testing is available. Some of the most severe and life-threatening examples of drug eruptions are erythema multiforme, Stevens–Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), hypersensitivity vasculitis, drug induced hypersensitivity syndrome (DIHS), erythroderma and acute generalized exanthematous pustulosis (AGEP). These severe cutaneous drug eruptions are categorized as hypersensitivity reactions and are immune-mediated. There are four types of hypersensitivity reactions and many drugs can induce one or more hypersensitivity reactions. The most common type of eruption is a morbilliform (resembling measles) or erythematous rash (approximately 90% of cases). Less commonly, the appearance may also be urticarial, papulosquamous, pustular, purpuric, bullous (with blisters) or lichenoid. Angioedema can also be drug-induced (most notably, by angiotensin converting enzyme inhibitors). The underlying mechanism can be immunological (such as in drug allergies) or non-immunological (for example, in photodermatitis or as a side effect of anticoagulants). A fixed drug eruption is the term for a drug eruption that occurs in the same skin area every time the person is exposed to the drug. Eruptions can occur frequently with a certain drug (for example, with phenytoin), or be very rare (for example, Sweet's syndrome following the administration of colony-stimulating factors). The culprit can be both a prescription drug or an over-the-counter medication. Examples of common drugs causing drug eruptions are antibiotics and other antimicrobial drugs, sulfa drugs, nonsteroidal anti-inflammatory drugs (NSAIDs), biopharmaceuticals, chemotherapy agents, anticonvulsants, and psychotropic drugs. Common examples include photodermatitis due to local NSAIDs (such as piroxicam) or due to antibiotics (such as minocycline), fixed drug eruption due to acetaminophen or NSAIDs (Ibuprofen), and the rash following ampicillin in cases of mononucleosis.