Erythema annulare centrifugum (EAC)

Synonyms: EAC

By Dr. Pascal Bafteh · last updated 09/2026

Definition & Subtypes

• Erythema annulare centrifugum (EAC, Darier 1916) = figurate (gyrate) erythema group with slowly centrifugal spread and border-emphasized morphology.
• Subtypes (Ackerman): Histologically / clinically distinguished are superficial + deep form — superficial = peripheral scaling ("trailing scale"), deep = firmer plaque without scaling.
• Special form: EAC-like neutrophilic dermatosis (paraneoplastic).

Pathogenesis & Triggers

• Pathogenesis: probably Type IV hypersensitivity to various antigens with perivascular lymphocytic infiltrate ("coat sleeve pattern").
• Triggers: Frequent triggers are infections (tinea, Borrelia, EBV, TB) + medications + tumors + pregnancy + foods.
• Paraneoplastic: Classic tumor association EAC deep: lymphoproliferative diseases (lymphomas, leukemias) — therefore tumor screening in refractory or atypical course.

Clinical Presentation

• Location: Preferred location is trunk + proximal extremities (gluteal / thigh).
• Morphology: Classic are annular plaques with raised peripheral ridge + central clearing + inner ("trailing") scaling.
• Trailing scale: "Wool thread phenomenon" = scaling sits inside / behind the advancing border ridge — pathognomonic and DD-relevant vs. tinea (peripheral scaling)!
• Course: Individual lesions 4–6 weeks, disease course recurrent over months–years.
• Symptoms: mostly asymptomatic, occasionally mildly pruritic.

Diagnostics

• Clinical diagnosis + trigger search obligatory!
• Laboratory / tests: Standard workup includes CBC + diff + liver/kidney values + ANA + Borrelia serology + Quantiferon + KOH prep + medication history.
• Skin biopsy: superficial form: perivascular lymphocytic infiltrate ("coat sleeve") in upper dermis; deep form: additionally in middle / deep dermis.
• KOH mandatory to exclude tinea!

Overview

Definition

• Chronic-recurrent, polyetiological, inflammatory skin disease with clinical significance as a "cutaneous reaction" (skin reaction to a variety of internal triggers).

Etiopathogenesis — Trigger Spectrum

• Malignant underlying conditions: Classically Lymphomas + Leukemias plus breast / ovarian / bronchial carcinoma.
• Infections: Candidiasis of the GIT (frequent!), Borrelia, HIV, COVID-19, Zoster.
• Parasitoses: Ascarids, other helminthic diseases.
• Autoimmune diseases: Autoimmune hepatitis, polyglandular autoimmune syndrome, Hashimoto's thyroiditis, Crohn's disease, Sarcoidosis, Polychondritis, Lupus erythematosus.
• Food allergens: Tomatoes, fish proteins, peanuts, molds in cheese.

Clinical Features

• Multiple, 1–2 cm red plaques that heal centrally and expand centrifugally → arcuate confluent.
• Typically smooth-surfaced; in some cases inner fine lamellar scale collar (important DD to Tinea, which scales on the outer side!).
• Tactile finding (almost pathognomonic): the leading edge feels like "wet wool thread".
• Profound variant (Darier pseudoform): lack of epidermal involvement — DD: Lupus erythematosus tumidus, Pseudolymphomas.

Differential diagnoses

• Erythema gyratum repens
• Pityriasis rosea
• Tinea corporis
• Urticaria
• Psoriasis vulgaris (plaque psoriasis)
• Granuloma annulare

Sources (selection)

1. Kim Erythema annulare centrifugum 2002

More inflammatory skin diseases

• Cheilitis granulomatosa (Miescher)
• Erythema nodosum
• Graft-versus-host disease (GvHD)
• Granuloma annulare
• Cutaneous sarcoidosis
• Lichen planus
• Lichen sclerosus
• Lichenoid drug eruption

Note: This page is intended for medical education and does not replace diagnosis or treatment decisions in individual cases. Treatment and follow-up content is available in the app.