**Core Concept**
Allergic fungal sinusitis (AFS) is a type of chronic fungal infection that affects the sinuses, characterized by an intense allergic reaction to fungal antigens. This condition is often seen in individuals with asthma or atopy, and is associated with a strong eosinophilic infiltrate in the affected sinuses.

**Why the Correct Answer is Right**
AFS is typically diagnosed based on a combination of clinical, radiological, and histopathological criteria. The key diagnostic features include a history of chronic sinusitis, nasal polyps, and a strong eosinophilic infiltrate on histopathology. Additionally, the presence of fungal elements such as hyphae or spores within the affected sinuses is a crucial diagnostic criterion.

**Why Each Wrong Option is Incorrect**
**Option A:** This option might seem plausible, but it is not a specific diagnostic criterion for AFS. While nasal congestion and facial pain are common symptoms of sinusitis, they are not unique to AFS and can be seen in other types of sinusitis as well.

**Option B:** This option is incorrect because nasal polyps are actually a characteristic feature of AFS. Nasal polyps are often seen in patients with AFS, and their presence can help to support the diagnosis.

**Option C:** This option is incorrect because a strong eosinophilic infiltrate is a hallmark of AFS. The presence of eosinophils in the affected sinuses is a key diagnostic feature of AFS, and can help to differentiate it from other types of sinusitis.

**Option D:** This option is incorrect because the presence of fungal elements is a crucial diagnostic criterion for AFS. The presence of fungal elements such as hyphae or spores within the affected sinuses is a key feature of AFS, and can help to support the diagnosis.

**Clinical Pearl / High-Yield Fact**
One important clinical pearl to remember is that AFS often requires a combination of medical and surgical management. While antifungal medications may be used to treat AFS, surgery is often necessary to remove the nasal polyps and fungal debris from the affected sinuses.

**Correct Answer:** A.