Which adverse effect is most commonly associated with inhaled corticosteroid use and can be minimized by rinsing the mouth after each inhalation?

Explanation

## Oropharyngeal Candidiasis with Inhaled Corticosteroids **Key Point:** Oropharyngeal candidiasis (thrush) is the most common local adverse effect of inhaled corticosteroids, occurring in 5–10% of patients due to local immunosuppression of the oropharyngeal mucosa and disruption of normal flora. ### Mechanism of Candidiasis Development 1. **Local immunosuppression:** ICS suppress local T-cell and neutrophil function in the oropharynx 2. **Dysbiosis:** Disruption of normal oral flora favors *Candida albicans* overgrowth 3. **Dose-dependent:** Higher ICS doses increase risk; more common with older formulations 4. **Preventable:** Simple mouth rinsing removes residual drug and candida spores **Mnemonic:** **THRUSH** = **T**opical corticosteroid **H**igh dose **R**esidual drug **U**nprevented **S**upression **H**ost flora ### Prevention and Management | Strategy | Efficacy | Mechanism | |----------|----------|----------| | Mouth rinsing after inhalation | 90% reduction | Removes residual ICS and spores | | Spacer device use | 50–70% reduction | Reduces oropharyngeal deposition | | Antifungal rinse (nystatin) | Therapeutic | Treats established candidiasis | | Dose reduction (if possible) | Variable | Decreases local immunosuppression | **Clinical Pearl:** The incidence of ICS-associated candidiasis has decreased with modern dry powder inhalers and metered-dose inhalers (MDIs) with spacers, which deposit less drug in the oropharynx. **High-Yield:** Candidiasis is reversible upon drug discontinuation or with antifungal therapy and does NOT require stopping ICS — patient education on mouth rinsing is sufficient prevention.