First report of mesalamine (5-aminosalicylic acid) as the causative agent in a case of acute generalized exanthamous pustulosis.

Acute generalized exanthamous pustulosis (AGEP)is a rare eruption of non-follicular sterile pustuleson a diffuse background of erythema and edema,commonly associated with fever and leukocytosis.Antibiotics are implicated in most cases; however,other drugs have been reported to cause AGEP. Wereport a case of a 73-year-old man with a historyof ulcerative colitis who presented with a diffusepustular rash, renal failure, elevated liver functiontests, and leukocytosis with neutrophilia. A week priorto admission, the patient was started on mesalamineto treat colitis. Upon admission, a workup includinga skin biopsy was performed and was consistentwith AGEP. Mesalamine was discontinued, and thepatient's skin eruption, renal function, liver functiontests, and leukocytosis subsequently improved.Mesalamine has an unknown mechanism of action.However, it is thought to be an anti-inflammatoryagent that blocks the production of leukotrienesand prostaglandins and is an immunosuppressantthat increases the release of adenosine, whichinterferes with leukocyte function. The decrease inprostaglandin synthesis or deregulation of leukocytefunction caused by mesalamine may be the etiologyin this case. Discontinuation of the offending agentleads to resolution of AGEP, as it did in this patient.

Oncostatin M promotes mucosal epithelial barrier dysfunction, and its expression is increased in patients with eosinophilic mucosal disease.

BACKGROUND: Epithelial barrier dysfunction is thought to play a role in many mucosal diseases, including asthma, chronic rhinosinusitis (CRS), and eosinophilic esophagitis. OBJECTIVE: The objective of this study was to investigate the role of oncostatin M (OSM) in epithelial barrier dysfunction in human mucosal disease. METHODS: OSM expression was measured in tissue extracts, nasal secretions, and bronchoalveolar lavage fluid. The effects of OSM stimulation on barrier function of normal human bronchial epithelial cells and nasal epithelial cells cultured at the air-liquid interface were assessed by using transepithelial electrical resistance and fluorescein isothiocyanate-dextran flux. Dual-color immunofluorescence was used to evaluate the integrity of tight junction structures in cultured epithelial cells. RESULTS: Analysis of samples from patients with CRS showed that OSM mRNA and protein levels were highly increased in nasal polyps compared with those seen in control uncinate tissue (P < .05). OSM levels were also increased in bronchoalveolar lavage fluid of allergic asthmatic patients after segmental allergen challenge and in esophageal biopsy specimens from patients with eosinophilic esophagitis. OSM stimulation of air-liquid interface cultures resulted in reduced barrier function, as measured by decreased transepithelial electrical resistance and increased fluorescein isothiocyanate-dextran flux (P < .05). Alterations in barrier function by OSM were reversible, and the viability of epithelial cells was unaffected. OSM levels in lysates of nasal polyps and uncinate tissue positively correlated with levels of α2-macroglobulin, a marker of epithelial leak, in localized nasal secretions (r = 0.4855, P < .05). CONCLUSIONS: These results suggest that OSM might play a role in epithelial barrier dysfunction in patients with CRS and other mucosal diseases.