**Question:** Which is most common side effect of inhaled beclomethasone dipropionate?

**Core Concept:** Beclomethasone dipropionate is a corticosteroid used for the treatment of asthma, primarily acting as an anti-inflammatory agent by suppressing the inflammatory response in the airways.

**Why the Correct Answer is Right:** The most common side effect of inhaled beclomethasone dipropionate is oral candidiasis, also known as thrush. This occurs due to the steroid's ability to suppress the immune system, particularly the local immune response in the oral cavity. This leads to a rise in the Candida albicans population, causing oral thrush.

**Why Each Wrong Option is Incorrect:**

A. **Thyroid dysfunction:** While systemic corticosteroids can cause thyroid dysfunction, inhaled corticosteroids primarily act locally, thus this side effect is less common and not the primary concern with inhaled beclomethasone dipropionate.

B. **Increased risk of pneumonia:** Inhaled corticosteroids do not increase the risk of pneumonia as much as oral or systemic corticosteroids. However, the focus here is on the most common side effect, not the overall risk profile.

C. **Impaired wound healing:** Inhaled corticosteroids do suppress the immune system locally, but the effect is limited to the respiratory tract. Therefore, impaired wound healing is less likely to occur with inhaled corticosteroids compared to systemic corticosteroids.

D. **Hypersensitivity reactions:** Inhaled corticosteroids are designed to be administered locally and are less likely to cause hypersensitivity reactions as compared to systemic corticosteroids.

**Clinical Pearl:** Inhaled corticosteroids, such as beclomethasone dipropionate, are generally well tolerated and have fewer systemic side effects compared to systemic corticosteroids. However, it is essential to educate patients about potential oral side effects and monitor for oral thrush during treatment.