Ketotifen use in a patient with fire ant hypersensitivity and mast cell activation syndrome

Clinical efficacy and safety of ketotifen in treating irritable bowel syndrome with diarrhea

OBJECTIVE

The aim of the study was to investigate the clinical efficacy and safety of ketotifen for the treatment of irritable bowel syndrome with diarrhea (IBS-D).

METHODS

A total of 108 enrolled IBS-D patients were randomly divided into a ketotifen group (n = 55) and a control (placebo) group (n = 53). The patients in the ketotifen group received ketotifen tablets (1 mg, oral) two times daily; patients in the control group received oral placebo for 8 weeks. Before and after 8 weeks of treatment, gastrointestinal symptoms, anorectal sensory function and the number and activity status of mast cells were assessed for both groups.

RESULTS

(1) The overall effective rate of gastrointestinal symptom improvement in the ketotifen group was significantly higher than that in the control group (76.4 vs. 37.7%, P < 0.001). (2) First sensation, defecation urgency and discomfort/pain threshold in the ketotifen group improved significantly after treatment (P < 0.05); no significant changes were observed in the control group (P > 0.05). (3) In the ketotifen group, the number of mast cells in the terminal ileum decreased, and the percentages of degranulated mast cells in the sigmoid colon, ascending colon and terminal ileum decreased significantly after treatment compared with before treatment; these differences were statistically significant (P < 0.01). In the control group, the number of mast cells and the percentages of degranulated mast cells in various sites did not change significantly before and after treatment (P > 0.05). (4) Six patients (10.9%) in the ketotifen group experienced drowsiness and fatigue, but the symptoms disappeared after 1 week of treatment.

CONCLUSION

Ketotifen significantly alleviated gastrointestinal symptoms and improved visceral hypersensitivity in patients with IBS-D. The therapeutic effect of ketotifen is related to a reduced number and decreased activity of mast cells in the intestinal mucosa, especially in the terminal ileum.

Pharmacotherapy of mast cell disorders

PURPOSE OF REVIEW

Mast cell disorders (MCDs) comprise mastocytosis and disorders referred to as mast cell activation syndrome and are caused by abnormal accumulation and/or activation of mast cells in tissues. Clinical signs and symptoms are protean; therefore, finding suitable treatment options for individual patients entails a challenge for clinicians. The purpose of this manuscript is to review the literature on the available therapeutic interventions in patients with MCD.

RECENT FINDINGS

Pharmacotherapy is mainly directed against the effects of mast cells and their mediators. The current recommendations are exclusively based on expert opinions due to the lack of controlled clinical trials. The targeted therapies aiming at blocking mutant KIT variants and/or downstream signaling pathways are currently being developed and may be considered in severely affected, therapy-refractory patients.

SUMMARY

There is currently no method for predicting the best available approach to control symptoms in individual patients with MCD. Therefore, a stepwise, individual-based approach in pharmacotherapy options appears to be most successful strategy and is recommended in all patients. The core component of the treatment in most patients is to control symptoms caused by mast cell mediator release, whereas cytoreductive therapies are mainly reserved for patients with advanced/aggressive systemic mastocytosis.

Differential Diagnosis of Chronic Urticaria and Angioedema Based on Molecular Biology, Pharmacology, and Proteomics

Differential diagnosis of urticaria and angioedema has been based on the phenotype as either acute or chronic depending on the duration of more than 6 to 8 weeks, respectively. Additional subdivisions include poorly defined terms such as idiopathic, spontaneous, or autoimmune. In this article, the author suggests that an increased understanding of the acquired and innate immune system and data from novel proteomic technology have blurred the lines between these categories of diagnosis. Specific molecular pathways and response to specific medications should be incorporated in classification and diagnosis schemes.