LAUSR

Methotrexate is a commonly used drug for the treatment of psoriasis, arthritis, and many forms of cancer. Methotrexate inhibits cancer cells from multiplying and reduces inflammation in both psoriasis and rheumatoid arthritis. In cancer, methotrexate inhibits cells access to folate causing folate deficiencies in patients taking the drug. While the mechanism of action of methotrexate in psoriasis and rheumatoid arthritis is unknown, use in these conditions can also result in folate deficiency. We report a patient who was admitted to the hospital with painful oral and esophageal ulcers which ultimately was attributed to folate deficiency in the setting of methotrexate use. The patient was a 63-year-old male with RA who presented to the ED with a 3-week history of mouth and throat pain upon swallowing. He was unable to eat and reported a 12-pound weight loss. Intraoral exam revealed areas of erythema with diffuse ulcerations on the upper and lower left labial mucosa, soft palate and anterior maxillary gingiva. A CT scan of the head, neck, and brain, and upper EGD were all within normal limits. The presentation was consistent with vesiculobullous disease and we recommended ruling out a drug induced etiology. Upon evaluation of the patient's laboratory values, we found he had megaloblastic macrocytic anemia (red cell diameter 11.5-14.5), which is consistent with folate deficiency. The patient's folate level was measured at 6ng/ml. The normal reference range is 7.3-20 ng/ml. 6 is considered quite low. The patient was administered folic acid and methotrexate was discontinued temporarily. The patient's oral lesions resolved, and the patient was discharged. This case illustrates the importance of collaboration between the primary team and the oral healthcare professional as well as the recognition that while methotrexate can cause oral ulcers, in the setting of folate deficiency the severity of oral ulcers may be exacerbated.