**Core Concept**
H1 blockers, also known as histamine H1 receptor antagonists, are a class of medications that competitively inhibit the action of histamine at the H1 receptor. This action results in the reduction of histamine-mediated symptoms such as vasodilation, increased vascular permeability, and smooth muscle contraction.

**Why the Correct Answer is Right**
The correct use of H1 blockers is to treat allergic reactions, particularly those involving the skin, respiratory tract, and gastrointestinal system. By blocking the H1 receptor, H1 blockers reduce the severity of symptoms such as pruritus, urticaria, angioedema, rhinitis, and anaphylaxis. This occurs through the inhibition of histamine release from mast cells and basophils, as well as the reduction of histamine-induced smooth muscle contraction and mucus secretion.

**Why Each Wrong Option is Incorrect**
* **Option A:** H1 blockers are not typically used to treat infections, as they do not possess antimicrobial properties.
* **Option B:** While H1 blockers can cause sedation as a side effect, this is not a primary indication for their use.
* **Option C:** H1 blockers are not primarily used to treat inflammatory conditions, although they may have anti-inflammatory effects through the inhibition of histamine release.

**Clinical Pearl / High-Yield Fact**
The first generation of H1 blockers, such as diphenhydramine, can cause significant sedation due to their ability to cross the blood-brain barrier and interact with central nervous system histamine receptors.

**Correct Answer: C.**