Can hypertension cause flushing?

Relationship Between High Blood Pressure and Flushing

High blood pressure itself does not typically cause flushing, but certain medications used to treat hypertension and hypertensive emergencies can cause flushing as a side effect. 1

Medications for Hypertension That Cause Flushing

Several medications used in the management of hypertension, particularly in hypertensive emergencies, are known to cause flushing:

1. Calcium Channel Blockers:

   • Nicardipine: Causes flushing, headache, and tachycardia 1
   • Other dihydropyridine calcium channel blockers can produce similar effects

2. Vasodilators:

   • Fenoldopam: Causes flushing, headache, and nausea 1
   • Hydralazine: Causes flushing, headache, and tachycardia 1
   • Nitroglycerin: Can cause flushing along with headache 1

3. Alpha-blockers:

   • Phentolamine: Causes flushing and tachycardia, particularly used for catecholamine excess 1

Hypertensive Emergencies and Flushing

In hypertensive emergencies (BP ≥180/120 mmHg with evidence of impending or progressive target organ damage), parenteral medications are often required for rapid BP reduction 1. Many of these medications cause flushing as a side effect due to their vasodilatory properties.

Hypertensive emergencies include conditions such as:

• Hypertensive encephalopathy
• Acute left ventricular failure
• Aortic dissection
• Acute myocardial infarction with hypertension
• Eclampsia
• Pheochromocytoma crisis 1

Mechanism of Medication-Induced Flushing

The flushing associated with antihypertensive medications occurs primarily due to:

• Direct vasodilation of cutaneous blood vessels
• Increased blood flow to the skin, particularly in the face
• Release of inflammatory mediators in some cases

Special Considerations

1. Pheochromocytoma: This condition can cause paroxysmal hypertension and flushing due to catecholamine release, but the flushing is due to the underlying condition rather than the hypertension itself 1

2. Alcohol consumption: Can cause both acute hypertension and flushing, particularly in individuals with genetic variations in aldehyde dehydrogenase (ALDH2) 2. This is not a direct effect of hypertension causing flushing but rather both symptoms occurring from the same trigger.

3. Medication interactions: Some antihypertensive medications may interact with other drugs or foods to cause flushing.

Clinical Implications

When a patient with hypertension presents with flushing:

1. Review their medication regimen, particularly recent changes or additions
2. Consider whether they are experiencing a hypertensive emergency requiring parenteral medications
3. Evaluate for other causes of flushing unrelated to hypertension (alcohol, menopause, carcinoid, mastocytosis)
4. If flushing is medication-related but not severe, reassurance may be appropriate as this side effect often diminishes over time

Bottom Line

While hypertension itself does not directly cause flushing, many medications used to treat hypertension—especially in emergency situations—commonly cause flushing as a side effect. When evaluating a patient with hypertension who experiences flushing, clinicians should first consider medication effects rather than attributing the flushing to high blood pressure itself.