Hello, Welcome to HCM Black eyes usually is the result of blunt trauma that causes bleeding beneath the thin eyelid skin, producing the characteristic blue-black discoloration. A fracture deep inside the skull can also cause black eyes to both eyes. People with sinusitis from allergies sometimes get allergic shiners , darkening under the eyes caused by inflamed and engorged blood vessels. Since you have history of allergies.you might have got this black eye probably. But i would still suggest you to consult your physician and undergo physical examination for confirmation of diagnosis. Hope you are happy with the answer. Thank you.