Erythema Annulare Centrifugum and Other Figurate Erythemas

Erythema Annulare Centrifugum and Other Figurate Erythemas: Introduction

Erythema Annulare Centrifugum at a Glance

Clinical pattern of annular expanding erythematous rings, which enlarge rapidly, fade, and then disappear, as new lesions appear.
Diagnosis of erythema annulare centrifugum is one of the exclusions.
Superficial and deep variants can be separated clinically and histologically. Deep form is usually lupus tumidus or erythema migrans.

The figurate erythemas include a variety of eruptions characterized by annular and polycyclic lesions. Classification of this group has always been controversial; the literature abounds with contradictions, uncertainties, and a bewildering array of synonyms. Darier in 1916 was the first to use the term erythema annulare centrifugum1 (EAC), although similar lesions had been described previously under other names. Table 43-1 lists the figurate erythemas and the differential diagnoses to consider.

Table 43-1 Migratory Erythemas

Disorder	Key Features
Erythema annulare centrifugum (EAC)	Slowly migrating lesions; often idiopathic.	This chapter
Erythema gyratum repens	Rapidly moving; usually cancer marker.	153
Erythema chronicum migrans	Annular lesions originating from tick bite; skin sign of Lyme borreliosis.	187
Lupus erythematosus	Most deep EAC is lupus tumidus. Annular lesions common in neonatal and subacute cutaneous LE; Ro/La antibodies should be sought; overlaps with Sjögren syndrome (especially in Asians).	155
Urticaria	Giant urticaria is often annular and migratory; patients have ordinary urticaria elsewhere and more pruritus.	38
Pityriasis rosea	Individual lesions closely resemble superficial EAC but pattern and course different	42
Bullous pemphigoid	Early lesions often urticarial and may be annular.	56
Erythema multiforme	Target lesions, usually acral, often mucosal disease; some lesions annular.	39
Dermatophyte infections and tinea versicolor	Many fungal infections are annular (ringworm); the scale contains hyphae or spores.	188
Psoriasis	Pustular and occasionally ordinary psoriasis may have annular lesions.	18
Erythema marginatum	Transient, rapidly spreading annular erythema; specific for rheumatic fever.	160
Necrolytic migratory erythema	Marker for glucagonoma; erosive perioral and acral lesions, but truncal lesions may be polycyclic.	153
Carrier state chronic granulomatous disease	Female carriers may have annular lupus erythematosus-like rash.	143
Hereditary lactate dehydrogenase M-subunit deficiency	Rare genodermatosis with annular erythematous and scaly lesions.	This chapter
Familial annular erythema	Extremely rare.	This chapter
Annular erythema of infancy	Many different disorders; must rule out neonatal lupus erythematosus.	This chapter

Epidemiology

EAC is an uncommon disorder. No epidemiologic data are available. There are only three large series in the literature: (1) 66 cases identified clinically,2 (2) 73 first diagnosed histologically,3 and (3) 90 carrying either a clinical or histological diagnosis.4 EAC appears to have no predilection for either sex or for any age group.

Etiology and Pathogenesis

Both the annularity and the peripheral spread of EAC have attracted speculation as to a possible mechanism. Most hypotheses have centered on interactions among inflammatory cells, their mediators, and ground substance as foreign antigens diffuse through the skin.5,6

While many possible triggers have been suggested, all are common problems and EAC is very rare, so a direct causality is impossible to prove. It is better to view EAC as idiopathic. In one series, 24 patients were closely evaluated, and in none of the cases was any definite cause found.7 Suspected triggers include bacterial8 and candidal9 infections, autoimmune diseases,10 menses,11 pregnancy,12 and even stress.13 Although medications are often identified as causing EAC in case reports, none regularly induces such lesions. EAC may be coupled with malignant neoplasms, with the eruption disappearing after treatment of the tumor and often returning as the tumor recurs.14–16 This paraneoplastic marker must be distinguished from metastatic tumors with an annular pattern.17,18

Clinical Findings

History

The history is most important in exploring the differential diagnostic considerations. In general, the lesions are asymptomatic but may be cosmetically disturbing.

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