Recurrent Esophageal Candidiasis Induced by Secukinumab: Discrepancy between Clinical Trials and Real-World Data

Dear Editor:

The Th17/interleukin (IL)-17 pathway is crucial in providing immunological protection against opportunistic pathogens, especially Candida albicans. Consequently, a substantial rise in Candida infection has been expected following the administration of IL-17 inhibitors¹. Nevertheless, published randomized clinical trials (RCTs) have shown no significant increase². Drug safety profiles based on RCTs, however, lack generalization owing to their strict eligibility criteria and limited study periods³,⁴. Therefore, real-world data is essential in understanding the safety profile of IL-17 inhibitors. Accordingly, we report a case of recurrent esophageal candidiasis induced by secukinumab.

A 72-year-old female patient undergoing 5 months of secukinumab therapy for psoriasis (Fig. 1) developed sudden signs of dysphagia. Endoscopic images revealed multiple white plaques throughout her esophagus (Fig. 2A). Mycological examination held in the local clinic confirmed esophageal candidiasis. Blood tests displayed no signs of neutropenia; the percentage of T cells (CD3), T helper cells (CD4), T suppressor cells (CD8), B cells (CD19), and NK cells (CD16/CD65) was within standards, excluding genetic immune disorders or drug-induced immunodeficiency. She had no previous history of candidiasis or a family history of immune deficiencies. In addition, the patient had no underlying disorders or systemic medications other than secukinumab. Accordingly, the patient was diagnosed with secukinumab-induced esophageal candidiasis.

Fig. 1. We received the patient’s consent form about publishing all photographic materials. Clinical and histopathological findings of the patient’s psoriatic lesions before the secukinumab treatment. (A) Scaly red-colored plaques symmetrically distributed on the back. (B) Histopathologic finding showing psoriasiform hyperplasia with neutrophil collections in the stratum corneum and stratum spinosum (H&E, ×40).

Fig. 2. Endoscopic findings of esophageal candidiasis before and after the antifungal treatment. (A) Confluent nodular white plaques throughout the esophagus. (B) Cleared esophageal mucosa after the systemic antifungal treatment.

After 2 weeks of systemic fluconazole treatment (50 mg/day), the endoscopic examination displayed cleared esophageal mucosa (Fig. 2B), along with symptom alleviation. Because her initial esophageal candidiasis was successfully managed with systemic antifungal medication, secukinumab treatment was maintained. In the consecutive months, however, the patient experienced a monthly relapse of esophageal candidiasis. All recurrences occurred after each secukinumab injection, and the patient repeated monthly systemic antifungal treatment for 4 months. To prevent further infection, secukinumab was switched to guselkumab, an IL-23 inhibitor. While maintaining clinical remission of psoriatic lesions, the patient has not experienced any recurrence of candidiasis within 8 months of guselkumab treatment.

Contrary to our case, the systematic review of RCTs in IL-17 inhibitors demonstrates no significant increase of Candida infection²; all cases of candidiasis were successfully treated with systemic or topical antifungal medications, and none required discontinuation of the biologic therapy.

Discrepancy in side effect profiles between the RCTs and real-world data, however, are not uncommon³. The generality of RCT data is weakened due to the strict eligibility criteria and short study periods. Large proportion of patients—especially those with old age and underlying comorbidities—are frequently excluded from the study participants⁴. A large cohort study conducted in Spain, for instance, demonstrates approximately 30% of psoriasis patients undergoing systemic treatment are ineligible for the RCTs owing to the rigid inclusion criteria⁵.

Hence, real-world data provide guidance to clinicians when under-reported side effects are encountered in clinical practice. In regards to our case, dysphagia can be easily neglected as a sign of indigestion in the elderly population. Therefore, clinicians administering IL-17 inhibitors should be aware that symptoms such as oral mucosal discomfort, dysphagia, or vaginal pruritus may indicate mucocutaneous candidiasis. When suspected, clinicians should confirm diagnosis via cultural or molecular studies and provide prompt management.