Principles of Systemic Therapy

Abstract

This chapter on systemic dermatological therapy aims to provide practising dermatologists with sufficient information about the most frequently used systemic medications to enable these to be used for treating skin disease to the maximum benefit and minimum detriment to their patients. The introduction covers general aspects of systemic therapy, including patient selection and education, risk reduction measures and the importance of good record keeping. Thereafter follows a detailed review of immunomodulatory and antimicrobial drugs, including antihistamines, antimalarial agents, azathioprine, ciclosporin, colchicine, dapsone, fumaric acid esters, glucocorticoids, hydroxycarbamide, methotrexate, mycophenolate mofetil, potassium iodide, protein therapies (biological drugs and intravenous immunoglobulin), retinoids, thalidomide, antibiotics, antifungal agents and antiviral drugs. The profile of each individual drug includes its pharmacological properties (formula and structure, pharmacodynamics, pharmacokinetics and, where relevant, pharmacogenetic aspects), potential adverse effects, contraindications, cautions, drug–drug interactions, pre‐treatment screening, dosage regimens, monitoring requirements and its range of licensed and off‐label dermatological usage.

Azathioprine hypersensitivity: A Sweet‐like syndrome

“…7 Genetic polymorphisms in the inositol triphosphate pyrophosphatase gene may also be associated with azathioprine hypersensitivity. 8 Photosensitivity with azathioprine has also been studied previously.…”

“…The imidazole (methyl nitroimidazole moiety) component in azathioprine was thought to associate with specific proteins generating haptens and causing type 3 hypersensitivity reactions after immune complex deposition over the vessel walls 7 . Genetic polymorphisms in the inositol triphosphate pyrophosphatase gene may also be associated with azathioprine hypersensitivity 8 . Photosensitivity with azathioprine has also been studied previously.…”