What is the pathophysiology of exfoliative dermatitis?

Updated: Aug 15, 2019
  • Author: David Vearrier, MD, MPH; Chief Editor: Barry E Brenner, MD, PhD, FACEP  more...
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Answer

The pathophysiologic processes resulting in exfoliative dermatitis vary with the underlying disorder responsible for the dermatitis. However, common to all conditions that cause exfoliative dermatitis is an increased rate of skin turnover. Normal epidermis has a continual turnover of epithelial cells. Cell division occurs near the basal layer. As cells move toward the periphery, they become well-keratinized. This process requires approximately 10-12 days. Cells subsequently remain in the stratum corneum for another 12-14 days prior to being sloughed.

In exfoliative dermatitis, the number of cells in the germinative layer and their mitotic rate is increased. The transit time of cells through the epidermis is shortened. As a result, the exfoliated scales are incompletely keratinized and contain material normally retained by the skin, including proteins, amino acids, and nucleic acids, which may result in a negative nitrogen balance. [2, 3] The amount of scale lost varies by underlying condition and its severity. Exfoliative dermatitis due to drug reactions, eczema, and psoriasis may result in the loss of 7.2 g, 9.6 g, and 22.6 g of scale per day, respectively (normal range, 500-1000 mg). Protein lost in that scale is 4.2 g, 5.6 g, and 12.8 g per day, respectively. The decreased transit time also results in impaired skin barrier function from incomplete keratinization, which may increase the absorption of medications administered transcutaneously through damaged skin.

Another common pathophysiologic process to all forms of exfoliative erythroderma is increased blood flow to the skin, which, in combination with impaired skin barrier function, results in increased insensible fluid loss through transpiration. Dehydration and reflex tachycardia are common. In severe cases, high-output cardiac failure may occur. Increased cutaneous blood flow also leads to increased heat loss, which may lead to a compensatory hypermetabolism and cachexia. [1]


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