Drug eruption

Drug eruption, also known as drug rash, refers to a variety of skin conditions that can occur as an adverse reaction to a drug. These reactions can range from mild rashes to severe and life-threatening conditions such as Stevens-Johnson syndrome and toxic epidermal necrolysis. Drug eruptions can affect individuals of any age, gender, or race and can be triggered by prescription medications, over-the-counter drugs, or herbal supplements.

Causes

Drug eruptions are caused by the body's immune response to a medication. The reaction can be immediate or delayed, with symptoms appearing hours to weeks after drug exposure. The exact mechanism varies depending on the type of drug eruption, but it generally involves the activation of the immune system by the drug or its metabolites, leading to inflammation and skin damage.

Types

There are several types of drug eruptions, each with distinct characteristics and causes. Some of the most common include:

• Exanthematous drug eruptions: The most common type, characterized by widespread red patches and sometimes accompanied by fever and malaise.
• Urticaria and angioedema: Hives and swelling, often appearing suddenly and sometimes as part of an allergic reaction.
• Fixed drug eruption: A localized reaction that recurs at the same site with re-exposure to the drug.
• Drug-induced hypersensitivity syndrome: A severe reaction that includes fever, rash, and internal organ involvement.
• Photosensitivity reactions: Skin reactions triggered by exposure to sunlight due to increased sensitivity caused by the drug.

Symptoms

Symptoms of drug eruptions vary widely but commonly include:

• Red, itchy rashes
• Swelling
• Blisters or lesions
• Peeling skin
• Fever and general malaise in severe cases

Diagnosis

Diagnosis of a drug eruption involves a thorough medical history, including a list of all medications taken, and a physical examination. Skin biopsy and blood tests may be performed to rule out other conditions and confirm the diagnosis. In some cases, patch testing or drug challenge tests are used to identify the specific drug causing the reaction.

Treatment

The primary treatment for a drug eruption is discontinuation of the offending medication. Mild reactions may be managed with antihistamines or topical corticosteroids to relieve itching and inflammation. Severe reactions may require systemic corticosteroids or hospitalization, especially if internal organs are involved. Rechallenge with the drug is generally avoided due to the risk of a more severe reaction.

Prevention

Prevention of drug eruptions involves careful review of a patient's drug history before prescribing new medications and avoiding drugs known to cause reactions in the individual. Patients with a history of drug allergies should wear medical alert bracelets and inform healthcare providers of their allergies.

See also

• Adverse drug reaction
• Dermatology
• Immunology