Flushing and Urticaria
Key Clinical Questions
What mechanisms cause cutaneous flushing?
How does one differentiate benign and malignant etiologies of flushing?
What tests and studies are useful to evaluate each potential diagnosis?
What treatments are available for each etiology?
What is the difference between acute and chronic urticaria?
What are the common causes of acute urticaria and chronic urticaria?
What is the appropriate workup for patients with acute or chronic urticaria?
In what clinical scenario is a skin biopsy indicated?
What is the appropriate workup when vasculitis is present on skin histology?
What therapies are available for acute and chronic urticaria?
Flushing results from vasodilation in the skin, produced by the release of vasoactive mediators or activity of the vasomotor nerves. It is characterized by sudden warmth and visible erythema, affecting the head (Figure 144-1), neck, and upper chest, regions of abundant superficial cutaneous vasculature. Flushing may be episodic or constant. When persistent, it may produce fixed facial erythema with a cyanotic tinge, secondary to the development of telangiectasias and large cutaneous blood vessels, containing slow-moving, deoxygenated blood (Figure 144-2).
Chronic persistent flushing.
The overwhelming majority of patients with flushing have common and relatively innocuous causes, with only a small proportion of cases being associated with tumors and other significant underlying medical problems (Table 144-1).
TABLE 144-1Differential Diagnosis of Flushing |Favorite Table|Download (.pdf) TABLE 144-1 Differential Diagnosis of Flushing
Common Causes of Benign Flushing
Drug-induced (partial list)
Niacin, calcium channel blockers, β-blockers, ACE inhibitors, nitroglycerin, sildenafil, vancomycin, NSAIDs, chemotherapy, morphine and other opiates
Uncommon to Rare Potentially Life-Threatening Flushing
Parkinson disease, multiple sclerosis, migraines, brain tumors, epilepsy,
dysautonomia and orthostatic hypotension, autonomic hyperreflexia, Horner syndrome, Frey syndrome
While the majority of patients with cutaneous flushing will be diagnosed as having a benign entity such as emotionally-induced flushing or rosacea, patients must be appropriately evaluated as to not miss a rare, but more life-threatening condition such as carcinoid syndrome or pheochromocytoma. While episodic flushing can be a normal physiologic response to external factors such as heat or alcohol, persistent flushing (>1 hour) is uncommon and should raise a red flag to the clinician that further investigation is warranted. Flushing is seldom the primary indication for hospital admission. However, the hospitalist should be familiar with the causes of flushing, as they may be seen in patients hospitalized for other ...