A 38-year-old man presents to an otolaryngology clinic with itchy eyes, periorbital swelling, and an itchy red rash on his face and arms.

A malar rash, or malar flush, is a rash on the nose and cheeks. Some call it a butterfly rash because of its shape. It’s almost always a symptom of another disorder, such as lupus or rosacea.

A 54-year-old woman presented to the emergency department at Beth Israel Lahey Hospital with episodes of unmeasured fever, left-sided facial and periorbital swelling, and conjunctival redness for ...