Differential Diagnosis for Headache behind Left Eye

• Single most likely diagnosis
  • Migraine: This is often characterized by unilateral headaches, which can be localized behind one eye. The pain is typically throbbing and can be accompanied by other symptoms such as nausea, vomiting, and sensitivity to light and sound.
• Other Likely diagnoses
  • Cluster headache: Known for causing severe, unilateral orbital or periorbital pain, often described as being behind one eye. These headaches occur in clusters or cycles and can be accompanied by nasal congestion, rhinorrhea, or ptosis on the affected side.
  • Tension headache: Although typically bilateral, tension headaches can sometimes present unilaterally and may be perceived as being behind the eye. They are usually described as a band or a squeezing sensation around the forehead.
  • Sinusitis: Inflammation of the sinuses, especially the frontal or ethmoid sinuses, can cause pain that is perceived behind the eyes. This is often accompanied by other symptoms such as facial pain, nasal congestion, and purulent nasal discharge.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed)
  • Temporal arteritis (Giant Cell Arteritis): This condition can cause unilateral headaches, often localized to the temporal region but can be perceived behind the eye. It's crucial to consider this diagnosis due to the risk of vision loss if not promptly treated.
  • Acute angle-closure glaucoma: Characterized by severe, unilateral eye pain, often accompanied by blurred vision, nausea, vomiting, and seeing halos around lights. This is a medical emergency requiring immediate treatment to prevent permanent vision loss.
  • Cavernous sinus thrombosis: A rare but potentially life-threatening condition that can cause headache, often accompanied by other symptoms such as fever, ptosis, proptosis, and cranial nerve palsies.
• Rare diagnoses
  • Trigeminal neuralgia: Although more commonly associated with facial pain, in rare cases, the pain can be perceived behind the eye. It's characterized by sudden, severe, shock-like or stabbing pain in parts of the face.
  • Occipital neuralgia: Involves the nerves that run from the base of the skull to the scalp and can cause pain that might be perceived behind the eye, though this is less common.
  • Idiopathic orbital inflammatory disease (IOID): A group of disorders characterized by inflammation of the orbit without any identifiable cause, which can cause pain behind the eye among other symptoms.