A “red ear” may be caused by a number of possible conditions. Many of the causes can affect one or both ears, while others (like infection) are usually unilateral.


Differential diagnosis of a unilateral red ear:

(1) red ear syndrome (RES)

(2) erythromelalgia

(3) perichondritis

(4) erysipelas or other infection

(5) contact dermatitis

(6) vascular disorder

(7) sunburn or thermal burn

(8) cold exposure

(9) irritation of the second or third cervical root

(10) migraine

(11) SUNCT or SUNA


Several of these conditions may involve autonomic dysfunction with inhibition of sympathetic vasconstriction affecting the ear.


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