Final answer:
Pale nasal turbinates distinguish allergic rhinitis from other forms of rhinitis, as they are typically pale and swollen due to histamine release during an allergic response.
Step-by-step explanation:
The physical examination finding that distinguishes allergic rhinitis from other rhinitis etiologies is D. Pale nasal turbinates. Allergic rhinitis, commonly known as hay fever, is characterized by an immune system reaction to harmless substances such as pollen, resulting in symptoms like red, watery, itchy eyes and sneezing.
When examining a patient, the nasal turbinates in allergic rhinitis are typically pale and may also appear swollen due to the release of histamines during an allergic response. This contrasts with the findings of other types of rhinitis, such as the common cold, where the turbinates might not necessarily be pale.
In comparison, clear rhinorrhea may be present in both allergic rhinitis and viral rhinitis, an erythematous pharynx is not specific as it can be found in many throat infections, and nasal flaring is generally associated with respiratory distress and not specific to rhinitis.