Acute generalized exanthematous pustulosis (AGEP) is a type of severe cutaneous adverse reaction, typically presenting with sterile pustules in predominantly flexural areas. However, AGEP may present without clinically evident pustules, making histopathologic investigation particularly important in instances of complex or unclear medication administration history.

Morbilliform drug eruptions in palliative care are often misattributed to active drugs, leading to inappropriate "opioid allergy" labels. Generic medications contain varying inactive excipients that can trigger delayed hypersensitivity. A man in his 70s with a prior history of ibuprofen-associated angioedema and metoclopramide-associated rash developed a pruritic morbilliform eruption after switching from a Mallinckrodt hydrocodone-acetaminophen product to a Camber oxycodone-acetaminophen formulation (National Drug Code [NDC] 31722-0951-05). During a washout period, the patient successfully tolerated SpecGx-manufactured morphine (NDC 00406-5118-01) and Aurobindo potassium chloride (NDC 65862-0987-99) while the rash resolved. Comparison of NDC data identified croscarmellose sodium as the likely culprit, as it was unique to the offending formulation. Clinicians should document the NDC rather than broad drug classes when reactions occur after a generic substitution to preserve future therapeutic options and ensure continued access to essential analgesia.

Drug-induced hypersensitivity syndrome (DIHS) is a rare, severe cutaneous adverse reaction that presents with rash, fever, and multiorgan involvement after medication or supplement exposure. Diagnosis is primarily clinical, although a skin biopsy may provide supportive evidence. Histologic features vary but generally reflect nonspecific epidermal and dermal inflammatory patterns. Rarely, DIHS presents with atypical features such as pustules, imitating acute generalized exanthematous pustulosis. We describe a case of a 68-year-old man who was started on carbamazepine for postoperative seizures and subsequently presented with a diffuse morbilliform rash with pustular components and distributive shock. He also displayed fever, lymphadenopathy, eosinophilia, acute kidney injury, and hepatitis, leading to a diagnosis of DIHS. A biopsy revealed interface dermatitis with eosinophils, subcorneal neutrophilic pustules, and dermal granulomatous inflammation. Although DIHS displays a broad spectrum of histologic features, a granulomatous reaction has been rarely reported. Herein, we describe a case of DIHS with granulomatous features.

Background: Drug reaction with eosinophilia and systemic symptoms (DRESS) and morbilliform drug eruption (MDE) are 2 distinct drug eruptions that can appear clinically similar at presentation. Given the significant morbidity of DRESS, there is a need for objective markers that can aid in early recognition.Objective: The purpose of this study is to explore the diagnostic potential of routine hematological data on or near the date of rash onset.Methods: We use machine learning as an exploratory method to identify any early hematological patterns capable of differentiating DRESS from MDE.Results: We found that lymphocyte count, pan-immune inflammation value, neutrophil-to-lymphocyte ratio, and platelet levels were strong discriminators of DRESS from MDE at initial presentation.Conclusions: These findings highlight the potential of hematologic profiles to enhance early diagnostic accuracy.

Meningoencephalitis involves inflammation of the meninges and brain parenchyma and is commonly associated with bacterial or viral infection. West Nile virus (WNV) is a mosquito-borne, single-stranded RNA arbovirus that rarely induces neuroinvasive disease. We present the first case of West Nile meningoencephalitis in Southwest Michigan.

Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is a serious, immune-mediated hypersensitivity condition marked by cutaneous eruptions, fever, hematologic abnormalities, and involvement of multiple organ systems. We report a case of DRESS syndrome precipitated by IV vancomycin and minocycline, presenting with fever, diffuse morbilliform rash, marked eosinophilia, transaminitis, and acute kidney injury. The diagnostic process was challenging because of overlapping features between infectious and autoimmune etiologies, necessitating careful clinical correlation, medication review, and application of the Registry of Severe Cutaneous Adverse Reactions (RegiSCAR) criteria. Early recognition enabled prompt discontinuation of the offending agents and initiation of systemic corticosteroids, resulting in gradual improvement in hepatic and renal function. This case underscores the need to maintain a heightened clinical suspicion for DRESS syndrome in patients treated with high-risk antibiotics. It reinforces the importance of prompt recognition and coordinated multidisciplinary care to reduce the risk of lasting organ injury.

Lorigerlimab is a dual bispecific antibody (BsAb) targeting cytotoxic T-lymphocyte-associated protein 4 and programmed cell death protein 1 that is used for treatment of advanced solid cancers such as metastatic castration-resistant prostate carcinoma. Reported cutaneous immune-related adverse events (irAEs) of lorigerlimab, such as pruritus and rash, are mostly manageable. However, to the best of our knowledge, the clinical histopathologic features of irAEs of the skin to dual immune checkpoint blockade with BsAbs have not been characterized. We report herein on lorigerlimab-associated lichenoid and vacuolar interface dermatitis in two patients with metastatic castration-resistant prostate adenocarcinoma. Case 1 had a violaceous, papular eruption and a lichenoid, perivascular histopathologic reaction pattern that responded well to temporary withholding of lorigerlimab and to corticosteroids. Case 2 presented with a more severe rash characterized by mixed clinical features of psoriasiform, eczematous, and morbilliform eruption and a histopathologic pattern of vacuolar interface changes with superficial perivascular lymphocytic infiltrate, scattered dyskeratotic keratinocytes, and focal acantholysis. The eruption was refractory to treatment, despite the patient withholding lorigerlimab, leading to complete discontinuation of lorigerlimab. This report highlights the importance of histopathologic evaluation in guiding treatment decisions for lorigerlimab-associated irAEs and underscores the need for further research into its dermatologic irAEs.

Drug reaction with eosinophilia and systemic symptoms (DRESS) is a rare but severe idiosyncratic hypersensitivity reaction, most commonly associated with antiepileptics and allopurinol. Although antibiotics are increasingly recognized as triggers, they remain underreported. The syndrome is characterized by fever, rash, eosinophilia, and variable organ involvement, with mortality. We report the case of a 26-year-old previously healthy male who presented with acute fever, diffuse morbilliform rash, facial edema, and eosinophilia following ceftriaxone exposure. His symptoms improved with corticosteroids and drug withdrawal, but he experienced a relapse shortly after starting Helicobacter pylori triple therapy. The second episode resolved with discontinuation of antibiotics and supportive care. Importantly, there was no renal, hepatic, or cardiac involvement in either episode, and the diagnosis of DRESS was confirmed with a RegiSCAR score of 3. This case highlights the variable presentation of DRESS, the diagnostic challenge posed by its overlap with other severe cutaneous adverse reactions, and the potential for relapse following re-exposure to structurally unrelated antibiotics. While the absence of systemic organ dysfunction contributed to a favorable outcome, the presence of positive autoantibodies underscores the importance of long-term follow-up due to the risk of autoimmune sequelae. Antibiotic-associated DRESS should be considered in patients presenting with rash, fever, and eosinophilia. Early drug withdrawal, structured diagnostic scoring, and long-term monitoring are essential to reduce morbidity and detect late complications.

Mycoplasma pneumoniae is a common cause of community-acquired pneumonia in school-aged children. Various cutaneous reactions to M. pneumonia have been described, including reactive infectious mucocutaneous eruption, morbilliform eruptions, and vasculitis. This study highlights two cases of Mycoplasma infection that presented with a morbilliform eruption and had clinical and laboratory findings similar to drug reaction with eosinophilia and systemic symptoms (DRESS), a pattern not well documented in the literature, and emphasizes the clinical manifestations that help distinguish between these conditions.