Blistering eruptions caused by drugs: Commentary

Abstract

C onsumption of drugs is increasing worldwide. The greater it becomes, the more physicians have to reckon with unexpected side effects. Among the untoward drug reactions, the cutaneous ones are the most obvious and often worry both doctor and patient more than other, possibly graver conditions. In addition, continued progress in the development of therapeutic agents and protocols poses difEculties for the dermatologist who faces the increasingly complex task of identifying, evaluating, and treating new adverse cutaneous reactions. This has prompted the publication of interesting monographs and books devoted entirely to cutaneous drug reactions. An issue in this journal dealing with “Unexpected Drug Reactions” l and the book Adverse Drug Reactions and the Skin2 are very good examples of the increased interest in this matter. Lately, bullous drug eruptions seem to predominate -not only the blistering eruptions classically related to drug intake (eg, fixed drug eruption, Stevens-Johnson syndrome, toxic epidermal necrolysis), but also certain bullous conditions usually thought to be idiopathic diseases (eg, pemphigus, bullous pemphigoid), for which a growing body of evidence points to the possible and not exceedingly rare induction by drugs. In fact, reports of pemphigus (or pemphigus-like syndrome) induced or triggered by drugs have increased so much in the last few years that today dermatologists are advised to consider a medicamentous origin whenever they observe pemphigus. The increased frequency of these unusual blistering eruptions may be connected with the widespread use of potent new drugs that, in certain conditions, are capable of causing intraepidermal or dermoepidermal detachment with or without immune medication.3 In this issue of Clinics in Dermatology, a panel of experts have been selected to report on a range of topics from certain misleading clinical aspects to possible pathomechanisms involved in blistering eruptions linked to drug intake. In particular, this issue stresses the crucial importance of close cooperation between clinicians and biologists and of a multidisciplinary approach in recent advances as well as in future research concerning cutaneous drug reactions. The fascinating article by Emiliano Panconesi on Historical Aspects reminds us that blister eruptions are less cited in the ancient literature than other elementary morphologic lesions. The great Alibert’s famous treatise arranged almost all the blistering eruptions into the First Order (“eczematous dermatoses”) and Third Order (“tineas”). Dealing with the epidemiology of bullous drug reactions, Stephen M. Breathnach and William G. Phillips note that patients with human immunodeficiency virus (HIV) infection or full-blown acquired immunodeficiency syndrome (AIDS) appear to be at markedly increased risk for bullous drug eruptions, especially those caused by sulfonamides, particularly co-trimoxazole (trimethoprim sulfamethoxazole). Narciss Mobini and A. Razzaque Ahmed superbly demonstrate how cutaneous reactions to drugs are modulated by the genetic background and immune status of the host. This may well explain the great clinical variety of eruptions reported after drug intake. Gianni Angelini, Gino A. Vena, Mauro Grandolfo, and Mario Mastrolonardo cover the wide field of iatrogenic contact dermatitis and eczematous reactions, a heap of clinical problems that no dermatologist can help coping with daily. An interesting observation on this topic is that highly sensitizing substances may be associated with a low incidence of allergies simply because they are little used in clinical practice (eg, mercury), whereas substances with a low or moderate sensitizing power may be very common causes of contact dermatitis because of their wide use (eg, neomycin). With respect to fixed drug eruption, Paolo Lisi and Luca Stingeni report some interesting data, including the fact that the inflammatory re-