What do you understand by erythema simplex?

Erythema simplex is a hyperæmic disorder characterized by redness, occurring in the form of variously-sized and shaped, diffused or circumscribed, non-elevated patches.

Name the two general classes into which the simple erythemata are divided.

Idiopathic and symptomatic.

What do you include in the idiopathic class?

Those erythemas due to external causes, such as cold and heat (erythema caloricum), the action of the sun (erythema solare), traumatism (erythema traumaticum), and the various poisons or chemical irritants (erythema venenatum).

What do you include in the symptomatic class?

Those rashes often preceding or accompanying certain of the systemic diseases, and those due to disorders of the digestive tract, stomachic and intestinal toxins, to the ingestion of certain drugs, and to use of the therapeutic serums.

Describe the symptoms of erythema simplex.

The essential symptom is redness—simple hyperæmia—without elevation or infiltration, disappearing under pressure, and sometimes attended by slight heat or burning; it may be patchy or diffused. In the idiopathic class, if the cause is continued, dermatitis may result.