Differential diagnosis in allergy.

The otolaryngic allergist must be able to distinguish between common nonallergic diagnoses that present very similarly to allergic conditions. This article describes a few of the vast myriad of conditions that must be ruled out before a diagnosis of allergy may be made. After reading this article clinicians will be able to identify various conditions, which will enhance their ability to appropriately make correct decisions for prompt and efficient management of their patients with allergic or nonallergic diseases of the head and neck.