Erythema

Erythema is redness of the skin caused by capillary congestion.

It can be caused by infection, massage, electrical treatments, acne medication, allergies, exercise or solar radiation (sunburn), and waxing and plucking of the hairs any of which can cause the capillaries to dilate, resulting in redness. Erythema is a common side effect of radiotherapy treatment due to patient exposure to ionizing radiation.

Associated conditions

 * Erythema ab igne
 * Erythema induratum
 * Erythema infectiosum (or fifth disease)
 * Erythema marginatum
 * Erythema migrans
 * Erythema multiforme (EM)
 * Erythema nodosum
 * Erythema toxicum
 * Palmar erythema

In about 30-50% of cases, the cause of Erythema is unknown.

Pathological Findings
Image courtesy of Professor Peter Anderson DVM PhD and published with permission © PEIR, University of Alabama at Birmingham, Department of Pathology