Erythema
Template:Short description Template:Distinguish Template:More citations needed Template:Infobox medical condition
Erythema (Template:Langx, Template:Ety) is redness of the skin or mucous membranes, caused by hyperemia (increased blood flow) in superficial capillaries.<ref>Template:Cite book</ref> It occurs with any skin injury, infection, or inflammation. Examples of erythema not associated with pathology include nervous blushes.<ref>Template:Cite encyclopedia</ref>
Types
- Erythema ab igne
- Erythema chronicum migrans
- Erythema induratum
- Erythema infectiosum (or fifth disease)
- Erythema marginatum
- Erythema migrans
- Erythema multiforme (EM)
- Erythema nodosum
- Erythema toxicum
- Erythema elevatum diutinum
- Erythema gyratum repens
- Keratolytic winter erythema
- Palmar erythema
Causes
It can be caused by infection, massage, electrical treatment, acne medication, allergies, psoriasis, mast cell activation syndrome (MCAS),<ref name="PMID35605594">Template:Cite journal</ref> exercise, solar radiation (sunburn), photosensitization,<ref>Template:Citation</ref> acute radiation syndrome, mercury toxicity, blister agents,<ref>Vesicant Template:Webarchive EFFECTS</ref> niacin administration,<ref>Template:Cite journal</ref> or waxing and tweezing of the hairs—any of which can cause the affected capillaries to dilate, resulting in redness. Erythema is a common side effect of radiotherapy treatment due to patient exposure to ionizing radiation.
Diagnosis
Erythema disappears on finger pressure (blanching), whereas purpura or bleeding in the skin and pigmentation do not. There is no temperature elevation, unless it is associated with the dilation of arteries in the deeper layer of the skin.Template:Citation needed