Differential Diagnosis for a 26-year-old Female with a 2-month History of Headache

Single Most Likely Diagnosis

• Tension Headache: This is the most common type of headache and is often described as a band or a squeezing sensation around the forehead, usually bilateral, and of mild to moderate intensity. The chronic nature (2 months) and the age of the patient make this a plausible diagnosis.

Other Likely Diagnoses

• Migraine: Although migraines are typically unilateral and can be severe, some patients may experience bilateral or mild headaches. The duration and potential triggers (e.g., hormonal changes, stress) could align with migraine, especially if there are associated symptoms like photophobia or nausea.
• Sinusitis: Chronic sinus infections can cause headaches, often described as a dull pain or pressure in the face, which might be mistaken for a primary headache disorder. The chronic nature of the headache could suggest a persistent infection.
• Medication Overuse Headache: If the patient has been taking frequent pain medication for her headaches, this could lead to a vicious cycle of medication overuse headaches, which are chronic and daily.

Do Not Miss Diagnoses

• Subarachnoid Hemorrhage: Although less likely given the chronic nature of the headache, a sudden onset of a severe headache (often described as "the worst headache of my life") could indicate a subarachnoid hemorrhage, which is a medical emergency.
• Brain Tumor: A new onset of headache in an adult, especially if it's worsening over time, could potentially be a sign of a brain tumor. Other symptoms might include seizures, focal neurological deficits, or signs of increased intracranial pressure.
• Idiopathic Intracranial Hypertension (IIH): This condition, also known as pseudotumor cerebri, can cause chronic headaches and is often associated with obesity and female gender. Papilledema and visual disturbances might be present.
• Temporal Arteritis: Although more common in older adults, temporal arteritis can cause new onset of headache and should be considered, especially if there are associated symptoms like jaw claudication or visual disturbances.

Rare Diagnoses

• Chiari Malformation: A structural defect in the cerebellum that controls balance can cause headaches, often worsened by coughing or straining.
• Trigeminal Neuralgia: A chronic pain condition that affects the trigeminal nerve, which carries sensation from your face to your brain. If the headache is unilateral and severe, with triggers like light touch, this could be considered.
• Hypothyroidism: In some cases, hypothyroidism can cause or exacerbate headaches, among other symptoms like fatigue, weight gain, and dry skin.

Each of these diagnoses should be considered in the context of the patient's full clinical presentation, including any additional symptoms, physical examination findings, and diagnostic test results.