Erythema (ERM)

Erythema (ERM): Definition, Symptoms, and Types
What is Erythema?
Erythema (ERM) is redness of the skin or mucous membranes, caused by increased blood flow (hyperemia) in superficial capillaries. It is a common symptom observed in many dermatological and systemic conditions and represents a response to irritation, inflammation, infection, or injury.
Symptoms of Erythema
- Area of skin or mucous membrane appears red, pink, or purplish due to blood vessel dilation.
- The redness usually blanches (fades) when pressure is applied.
- May be accompanied by warmth, swelling, tenderness, or itching depending on the cause.
- Visible primarily in lighter skin tones and may be subtle or difficult to detect in darker skin.
Common Types of Erythema
- Erythema Multiforme: Immune-mediated skin reaction causing target-shaped lesions, often triggered by infections (herpes simplex) or medications. Symptoms include rash, fatigue, fever, and sometimes mucosal involvement.
- Erythema Nodosum: Tender, red nodules typically found on the shins, associated with infections, autoimmune diseases, or medications. Accompanied by systemic symptoms such as fatigue and joint pain.
- Erythema Infectiosum (Fifth Disease): Caused by parvovirus B19, commonly presents with a “slapped cheek” rash in children.
- Erythema Migrans: Expanding red rash with central clearing, characteristic of Lyme disease.
- Other types include erythema marginatum, erythema toxicum, erythema gyratum repens, and palmar erythema.
Causes of Erythema
- Infections (bacterial, viral, fungal)
- Allergic or hypersensitivity reactions
- Autoimmune diseases
- Physical stimuli such as sunburn, heat, or trauma
- Medication side effects
- Dermatologic conditions including psoriasis and dermatitis
Summary
Erythema is an important clinical sign indicating increased blood flow related to various causes. Recognizing its different forms and associated symptoms helps guide diagnosis and treatment.
Consult with Our Team of Experts Now!
For evaluation and management of erythema related to diverse medical conditions, consult our dermatology specialists and internal medicine specialists today.
References:
Kang H, Lee J. Erythema: Definition, Types, and Clinical Significance. Dermatol Clin. 2024;42(4):515-526. doi:10.1016/j.det.2024.07.001. Available at: https://doi.org/10.1016/j.det.2024.07.001















