Definition
A skin rash that develops as a result of taking a drug, i.e. as a skin reaction to a certain drug substance, is also called a drug exanthema (exanthema = large-area, uniform skin rash). This is an allergic reaction that occurs after taking drugs or after local application of drugs on the skin, whereby the exanthema is the most common side effect of drug intake on the skin. The basis for the skin reaction is either a genuine drug allergy or a pseudoallergy.
Causes
In principle, any drug can cause a skin rash, but in some cases the development of a drug exanthema has been observed more frequently. These include in particular various antibiotics, painkillers and anti-convulsive drugs (antiepileptics). The basis for this is an incorrect reaction of the body’s own immune system to foreign substances that are actually non-infectious or dangerous, with an inflammatory reaction, which in this case manifests itself in the form of a skin rash. In principle, any drug can induce a drug exanthema. The most common drugs that can cause a drug-induced rash in the context of a drug allergy or pseudoallergy include the following:
- Antibiotics: Penicillins (see also: skin rash after penicillin), cephalosporins, sulfonamides
- Painkillers: Ibuprofen, Diclofenac, Naproxen, ASS
- Insulin
- Heparins
- Thyroid hormones: iodine, thiouracils, perchlorates
- Antiepileptic drugs (drugs for seizures) and psychotropic drugs
- Gout medications: Allopurinol
- Cardiovascular drugs: e.g. ACE inhibitors
- Vaccines, contrast media, local anaesthetics, muscle relaxants (suxamethonium), sleeping pills (barbiturates)
Associated symptoms
A rash of red spots, papules, pustules, blisters and/or wheals, often affecting the extremities or trunk (abdomen, back, chest), can sometimes be accompanied by diarrhea, nausea, vomiting, a feeling of illness or cold and fever. The rash may also be accompanied by more or less severe itching. Whether and how pronounced the (accompanying) symptoms occur varies greatly from individual to individual.
A drug exanthema can sometimes be accompanied by itching, which can be more or less pronounced – here, individual differences can be observed. Whether and to what extent itching occurs depends, among other things, on how the rash manifests itself. Not every drug exanthema manifests itself in the same way. The rash can manifest itself in different ways, ranging from small to large spots of redness and pustules to the formation of wheals (urticaria). Hives, for example, are accompanied by particularly severe itching.
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