Nine other case series meeting the search criteria were found. Of the reported 117,669 injections performed, three resulted in visual complications yielding an estimated visual complication rate of %. All three of these events resolved spontaneously and resulted in no permanent visual deficits. A total of 19 reports of visual complications following intranasal steroid injections were discovered. Of these, the majority have insufficient detail regarding the injection technique or cite gross deviation from the correct injection protocol.
It seems strange, then, that allergic reactions to corticosteroids actually occur—especially since these medications are used to treat allergic reactions. While severe allergic reactions to corticosteroids are extremely rare, they do in fact occur. Most allergic reactions to corticosteroids are less severe, however, and result from the topical formulations—occurring in up to 6% of people. Allergic reactions to oral or injected formulations are rarer, occurring in less than 1% of people. Causes of allergic reactions to corticosteroids may be due to IgE antibodies , or as a result of delayed-type hypersensitivity reactions caused by T-cells (a type of white blood cell).
The precise mechanism through which fluticasone propionate affects rhinitis symptoms is not known. Corticosteroids have been shown to have a wide range of effects on multiple cell types (., mast cells, eosinophils, neutrophils, macrophages, lymphocytes) and mediators (., histamine, eicosanoids, leukotrienes, cytokines) involved in inflammation. In 7 trials in adults, Flonase Nasal Spray has decreased nasal mucosal eosinophils in 66% of patients (35% for placebo) and basophils in 39% of patients (28% for placebo). The direct relationship of these findings to long-term symptom relief is not known.