Piroxicam-induced photodermatitis. Cross-reactivity among oxicams. A case report

Hypersensitivity reactions to nonsteroidal anti-inflammatory drugs: from phenotyping to genotyping

PURPOSE OF REVIEW

Nonsteroidal anti-inflammatory drugs (NSAIDs) are the most frequent drugs involved in hypersensitivity drugs reactions. Both immunological and nonimmunological mechanisms can be involved. We describe the different phenotypes as well as analyze the genetic basis for NSAIDs hypersensitivity.

RECENT FINDINGS

Five major clinical entities are currently accepted in the classification of hypersensitivity reactions to NSAIDs. Three are mediated by nonspecific immunological mechanisms: NSAIDs-exacerbated respiratory disease, NSAIDs-exacerbated cutaneous disease and NSAIDs-induced urticaria/angioedema. Two are mediated by specific immunological mechanisms: single-NSAID-induced urticaria/angioedema or anaphylaxis and single-NSAID-induced delayed hypersensitivity reactions. The classification becomes more complex if we consider that in an important number of cases skin and airway involvement can occur, as well as the participation of other organs.

SUMMARY

Hypersensitivity reactions to NSAIDs are more complex than for other drugs like betalactams in terms of the number and types of reactions elicited, and mechanisms involved. As NSAIDs are the most frequent cause of drug hypersensitivity, it is feasible to gather a sufficient number of cases for undertaking pharmacogenetic studies.

Adverse drug events in the oral cavity

Adverse reactions to medications are common and may have a variety of clinical presentations in the oral cavity. Targeted therapies and the new biologic agents have revolutionized the treatment of cancers, autoimmune diseases, and inflammatory and rheumatologic diseases but have also been associated with adverse events in the oral cavity. Some examples include osteonecrosis, seen with not only bisphosphonates but also antiangiogenic agents, and the distinctive ulcers caused by mammalian target of rapamycin inhibitors. As newer therapeutic agents are approved, it is likely that more adverse drug events will be encountered. This review describes the most common clinical presentations of oral mucosal reactions to medications, namely, xerostomia, lichenoid reactions, ulcers, bullous disorders, pigmentation, fibrovascular hyperplasia, white lesions, dysesthesia, osteonecrosis, infection, angioedema, and malignancy. Oral health care providers should be familiar with such events, as they will encounter them in their practice.

[Drug patch tests in the investigation of cutaneous adverse drug reactions]

Cutaneous adverse drug reactions (CADR) are a frequent problem in clinical medicine. Since patients are often on multiple drug regimes, it is often difficult to pinpoint the relevant drug from history alone. Besides clinical and chronological parameters, patch testing with the suspected compound has been reported as helpful in determining the cause of a CADR and in studying the physiopathological mechanisms involved in such reactions. The key advantage of drug patch tests is that they can be performed using any commercialized form of drugs and without hospital surveillance because they only rarely induce adverse reactions, which in any event are mild. The method for performing drug patch tests has been described, and requisite commercialized material is now commercially available, failing which the best approach is to dilute the drug in its commercialized form at 30% in petrolatum or in water. The results of drug patch tests depend on the drug tested and the clinical features of the initial CADR. They appear to be of value in investigating maculopapular rash, eczema at drug injection sites, photosensitivity (photopatch tests with 5J of irradiation), fixed drug eruption (testing at the sequelae site), acute generalized exanthematous pustulosis and symmetrical drug-related intertriginous flexural exanthema. Although less widely used, they are probably also of value in drug reaction with eosinophilia and systemic symptoms (DRESS) but they are of less use in Stevens-Johnson syndrome (SSJ) and Lyell's syndrome. Many drugs have been reported as producing positive patch tests, and most of these are summarized in a summary table of this literature review.

Cutaneous and ocular adverse reactions in a dog following meloxicam administration

The present report addresses the development of cutaneous and ocular reactions possibly related to meloxicam administration in a dog. Based on clinical signs and absence of laboratory data compatible with the other differential diagnoses considered, the possibility of an adverse drug reaction (ADR) due to meloxicam was considered. Skin biopsy revealed haemorrhage of the superficial and deep dermis, associated with hyperplasia of endothelial cells and epidermal sloughing. Vasculitis in the deep dermis was also noted. Such lesions were considered compatible with an ADR. Although the owner was not aware of any previous allergic reaction to drugs, the animal had a clinical history of atopic dermatitis. Meloxicam is a nonsteroid anti-inflammatory drug (NSAID) in the oxicam family, indicated for the control of inflammation and pain in acute and chronic musculoskeletal disorders in dogs. Although meloxicam is usually well tolerated, the present clinical case represents an alert to practitioners about the potential role of NSAIDS in ADRs in dogs with a history of allergic cutaneous diseases.