Although the rate of acute severe adverse cutaneous reactions to medications is low, these reactions can affect anyone who takes medications and can result in death or disability1. Even a small number of cases associated with a particular drug may alter the recommendations for its use2–4. Prompt differentiation of severe adverse cutaneous reactions from less serious skin disorders may be difficult. Rapid recognition of severe reactions is essential. Prompt withdrawal of the offending drug is often the most important action to minimize morbidity. Adverse cutaneous reactions to drugs are frequent, affecting 2 to 3 percent of hospitalized . . .

Severe Adverse Cutaneous Reactions to Drugs

Since the first description by Saltzstein in 1959, the denomination of drug-induced pseudolymphoma was used to describe two cutaneous adverse drug reactions with a histological picture mimicking malignant lymphoma. On the basis of clinical presentation, this term includes two different patterns: (1) hypersensitivity syndrome which begins acutely in the first 2 months after the initiation of the drug and associates fever, a severe skin disease with characteristic infiltrated papules and facial edema or an exfoliative dermatitis, lymphadenopathy, hematologic abnormalities (hypereosinophilia, atypical lymphocytes) and organ involvement such as hepatitis, carditis, interstitial nephritis, or interstitial pneumonitis. The cutaneous histological pattern shows a lymphocytic infiltrate, sometimes mimicking a cutaneous lymphoma, and the mortality rate is about 10%. When organ involvement exists, corticosteroids are often prescribed with dramatic improvement. Relapses may occur. (2) drug-induced pseudolymphoma which has a more insidious beginning with nodules and infiltrated plaques appearing several weeks after the beginning of the drug without constitutional symptoms. A pseudolymphoma pattern is seen on cutaneous histological slides. Complete improvement is usual after drug withdrawal, but a delayed lymphoma is possible. To decrease the ambiguity of the denomination of hypersensitivity syndrome, we propose the term of DRESS (Drug Rash with Eosinophilia and Systemic Symptoms).

Drug-induced pseudolymphoma and drug hypersensitivity syndrome (Drug Rash with Eosinophilia and Systemic Symptoms: DRESS).

The DRESS Syndrome: A Literature Review

It is generally accepted that there is neither a well-defined nor a consistent link between the formation of drug-protein adducts and organ toxicity. Because the potential does exist, however, for these processes to be causally related, the general strategy at Merck Research Laboratories has been to minimize reactive metabolite formation to the extent possible by appropriate structural modification during the lead optimization stage. This requires a flexible approach to defining bioactivation issues in a variety of metabolism vectors and typically involves the initial use of small molecule trapping agents to define the potential for bioactivation. At some point, however, there is a requirement to synthesize a radiolabeled tracer and to undertake covalent binding studies in vitro, usually in liver microsomal (and sometimes hepatocyte) preparations from preclinical species and human, and also in vivo, typically in the rat. This paper serves to provide one pragmatic approach to addressing the issue of bioactivation from an industry viewpoint based on protocols adopted by Merck Research Laboratories. The availability of a dedicated Labeled Compound Synthesis group, coupled to a close working relationship between Drug Metabolism and Medicinal Chemistry, represents a framework within which this perspective becomes viable; the overall aim is to bring safer drugs to patients.

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Drug-protein adducts: an industry perspective on minimizing the potential for drug bioactivation in drug discovery and development.

BackgroundCases of severe drug hypersensitivity, demonstrating a variable spectrum of cutaneous and systemic involvement, are reported under various names, especially drug reaction with eosinophilia and systemic symptoms (DRESS). Case definition and overlap with other severe cutaneous adverse reactions (SCAR) are debated. ObjectivesTo analyse the spectrum of signs and symptoms of DRESS and distribution of causative drugs in a large multicentre series. Patients and methodsRegiSCAR, a multinational registry of SCAR, prospectively enrolled 201 potential cases from 2003 to mid-2009. Using a standardized scoring system, 117 cases were validated as showing probable or definite DRESS. ResultsThe male/female ratio was 080; females were borderline significantly younger than males. Next to the ubiquitous exanthema, the main features were eosinophilia (95%), visceral involvement (91%), high fever (90%), atypical lymphocytes (67%), mild mucosal involvement (56%) and lymphadenopathy (54%). The reaction was protracted in all but two patients; two patients died during the acute phase. Drug causality was plausible in 88% of cases. Antiepileptic drugs were involved in 35%, allopurinol in 18%, antimicrobial sulfonamides and dapsone in 12% and other antibiotics in 11%. The median time interval after drug intake was 22days (interquartile range 17-31) for all drugs with (very) probable causality, with differences between drugs. ConclusionThis prospective observational study supports the hypothesis that DRESS is an original phenotype among SCAR in terms of clinical and biological characteristics, causative drugs, and time relation. The diversity of causative drugs was rather limited, and mortality was lower than that suggested by prior publications.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/bjd.12501

Drug reaction with eosinophilia and systemic symptoms (DRESS): an original multisystem adverse drug reaction. Results from the prospective RegiSCAR study

Arene oxide metabolites of aromatic anticonvulsants (phenytoin, phenobarbital, and carbamazepine) may be involved in the pathogenesis of hypersensitivity reactions. We investigated 53 patients with clinical sensitivity to anticonvulsants by exposing their lymphocytes in vitro to drug metabolites generated by a murine hepatic microsomal system. The diagnosis of a hypersensitivity reaction was corroborated by in vitro rechallenge for each drug (phenytoin, n = 34; phenobarbital, n = 22; carbamazepine, n = 25) when cytotoxicity (% dead cells) exceeded 3 SD above the mean result for controls. Cross-reactivity among the drugs was noted. 7 out of 10 patients who had received all three anticonvulsants had adverse reactions to each. 40 out of 50 patients tested to all three drugs in vitro were positive to each. Adverse reactions were indistinguishable among anti-convulsants. Skin rash (87%), fever (94%), hepatitis (51%), and hematologic abnormalities (51%) were common clinical features of each drug. 62% of reactions involved more than two organs. Cells from patients' parents exhibited in vitro toxicity that was intermediate between values for controls and patients. In vitro testing can help diagnose hypersensitivity to anticonvulsants. Cells from patients may also be used for prospective individualization of therapy to decrease risk of adverse reaction. Cross-reactivity among the major anticonvulsants is common and should be considered before deciding on alternative therapy.

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S P Spielberg

Papers

Anticonvulsant hypersensitivity syndrome. In vitro assessment of risk.