Chapter 141. Flushing and Urticaria

1. What mechanisms cause cutaneous flushing?

2. How does one differentiate benign and malignant etiologies of flushing?

3. What tests and studies are useful to evaluate each potential diagnosis?

4. What treatments are available for each etiology?

5. What is the difference between acute and chronic urticaria?

6. What are the common causes of acute urticaria and chronic urticaria?

7. What is the appropriate workup for patients with acute or chronic urticaria?

8. In what clinical scenario is a skin biopsy indicated?

9. What is the appropriate workup when vasculitis is present on skin histology?

10. What therapies are available for acute and chronic urticaria?

Flushing results from vasodilation in the skin, produced by release of vasoactive mediators or activity of the vasomotor nerves. It is characterized by sudden warmth and visible erythema, affecting the head (Figure 141-1), 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 141-2).

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 141-1).

Benign Cutaneous Flushing

Flushing is most often physiologic (benign cutaneous flushing). It is more common in women than men. Common precipitants include fever, exercise, warm temperatures, spicy foods, and alcohol. In fair-skinned persons, flushing (or blushing) often occurs in response to strong emotion, which perhaps evolved as a nonverbal means to express arousal or display vigor. Although blushing historically was thought attractive, it may produce anxiety and distress in some contemporary patients.

Rosacea

Rosacea is characterized by acneiform inflammation of the central face, with erythema, flushing episodes, telangiectasias, and often papules and pustules. Eye lesions, such as blepharitis, conjunctivitis, episcleritis, and keratitis with corneal ulcers also occur. It is common in ...