Fluoxetine-Induced Severe Oral Ulceration in a 13-Year-Old Girl

Introduction

Fluoxetine is the drug of choice for adolescent depression (Hetrick et al. 2012). A meta-analysis has stated its superiority over cognitive behavior therapy and other medications (Ma et al. 2014).

Oral ulcers are inflammatory lesions of oral mucosa that are seen in about 20% of the population (Scully and Shotts 2000). Oral ulceration related to sertraline has been reported in the past (Bertini et al. 2009). We could not access any scholarly articles on oral ulceration induced by fluoxetine. In this study, we report a case of severe oral ulceration in an adolescent girl who was treated for depressive disorder. An informed written consent was obtained from the mother and assent from the adolescent for publication of clinical findings.

Case Report

S.K. ^* is a 13-year-old school student seen as an outpatient at the Colombo North Teaching Hospital, a 1387-bed tertiary care hospital in Ragama, Sri Lanka. She was suffering from worsening irritability, low mood, lack of interest in academic activities, and suicidal ideation for a period of six months. S.K. did not have a past history of significant oral ulceration or systemic illness. There were no features of any physical disorder in her assessment, including oral ulceration.

She was diagnosed as having major depressive disorder of severe degree according to the fifth edition of Diagnostic and Statistical Manual of Mental Disorders (American Psychiatric Association, 2013). She was commenced on cognitive behavior therapy in combination with fluoxetine 10 mg per day.

At 2 weeks, S.K. reported lessening of her depressive symptoms, and at 4 weeks, she had clinically improved with returning of interest in academic activities and absence of suicidal ideation. After 8 weeks, S.K. reported multiple painful oral ulcers of few days' duration, which had made her avoid solid food, resorting only to cold beverages. On examination, multiple oval-shaped shallow lesions were seen, with a yellowish exudate in the center and surrounding erythematous background without any other positive physical findings.

She was referred for general pediatric and later dermatological assessment, which did not reveal any cause for the ulceration. Even though S.K. was requested to continue fluoxetine, the parents had defaulted on medications, including local applications provided by the dermatologist, fearing further exacerbation of ulceration.

In 12 weeks' time, the girl returned with an exacerbation of depressive symptoms and complete resolving of oral lesions. After a careful assessment, she was recommenced on fluoxetine after reassuring them that the oral lesions are unlikely to be due to the antidepressant. At 14 weeks, S.K. returned with recurrence of similar oral ulcers, which were painful enough to stop her attending school. She had already stopped fluoxetine 7 days before her latest clinic visit and was commenced on sertraline at a dose of 25 mg per day. Fluoxetine and sertraline are the only available selective serotonin reuptake inhibitors in the free government health sector. With sertraline, her depressive symptoms improved, and at six months follow-up, she was clinically euthymic, attending school and completely devoid of oral ulcers.

Discussion

The cause of oral ulceration was attributed to fluoxetine due to chronological association with its commencement and recurrence on reintroduction. Even though oral ulceration due to different etiologies is common, it has not been reported to be related to fluoxetine use in the past (Scully and Shotts 2000). Further studies are required to explore this association.