Differential Diagnosis for Bruise on Forehead with Associated Symptoms

Single Most Likely Diagnosis

• Trauma or Contusion: The presence of a bruise on the forehead, which resembles an "in vein" appearance, along with visible veins surrounding the area, suggests a traumatic injury. The symptoms of tingling in the face and a sharp headache in the temple could be related to the trauma, possibly indicating a minor concussion or a scalp injury affecting nerve endings.

Other Likely Diagnoses

• Vascular Injury or Vasculitis: The description of the bruise and the visibility of surrounding veins might suggest a vascular component to the injury, possibly a small vascular injury or an early sign of vasculitis, which could explain the headache and facial tingling.
• Migraine or Tension Headache: The sharp headache in the temple and facial tingling could also be indicative of a migraine or tension headache, possibly triggered by the initial trauma or stress.

Do Not Miss Diagnoses

• Subdural Hematoma or Intracranial Hemorrhage: Although less likely given the description, it's crucial not to miss a potential subdural hematoma or intracranial hemorrhage, especially if the patient has experienced significant trauma. These conditions can present with headache, neurological symptoms, and sometimes with external signs of trauma.
• Temporal Arteritis: This condition, although more common in older adults, can present with headache, visual disturbances, and sometimes facial pain or tingling. It's a critical diagnosis not to miss due to the risk of vision loss if not promptly treated.

Rare Diagnoses

• Cavernous Sinus Thrombosis: A rare but serious condition that could potentially follow facial trauma, especially if there's an infection involved. Symptoms might include headache, facial pain, and possibly visual disturbances.
• Neurological Disorders (e.g., Multiple Sclerosis, Trigeminal Neuralgia): While less directly related to the initial presentation of a bruise, these conditions could potentially explain some of the neurological symptoms such as facial tingling and should be considered if other explanations are ruled out and symptoms persist or worsen.

Suggestion on How to Proceed with the Patient

Given the range of potential diagnoses, a thorough history and physical examination are essential. This should include assessing the patient's neurological status, vision, and checking for any signs of infection or further injury. Imaging studies (e.g., CT or MRI of the head) may be necessary to rule out serious conditions like intracranial hemorrhage or to further evaluate the extent of any trauma. Depending on the findings, consultation with specialists such as neurology or vascular surgery may be warranted. Monitoring the patient's condition and adjusting the treatment plan based on evolving symptoms and diagnostic findings is crucial.