Erythema Annulare Centrifugum
- Erythema annulare centrifugum (EAC) is an eruption characterized by erythematous annular or figurate plaques that demonstrate central clearing and a distinctive trailing scale along the inner border.
- Lesions tend to occur on the hips and lower extremities but can appear on the trunk, face, and upper extremities. Lesions have not been reported to affect the palms, soles, or mucosa.
- First identified by Darier in 1916 and later classified in 1978 into two subtypes: deep and superficial. Superficial lesions demonstrate a collarette of trailing scale, whereas deep lesions do not.
- Most often idiopathic but sometimes found in association with an underlying disease process
- EAC can be recurrent and wax and wane over months to years.
- System(s) affected: skin
- Synonym(s): deep/superficial gyrate erythema; erythema perstans; palpable migrating erythema
- No predominant age: EAC has been reported in all age groups, from infants to geriatric patients.
- No known predilection to race or sex
- A study in England estimated annual incidence of EAC at 1/100,000 population (1).
- Peak incidence is during the 5th decade of life.
Etiology and Pathophysiology
- Pathophysiology unknown, but delayed hypersensitivity from inciting antigens may induce EAC
- Hypersensitivity reaction postulated to be due to a variety of factors including the following:
- Medications: Commonly nonsteroidal anti-inflammatory drugs (NSAIDs), antimalarials such as hydroxychloroquine, diuretics, and other medications such as amitriptyline, finasteride, azacitidine, and pegylated interferon α-2b when combined with ribavirin have also been reported.
- Arthropod bites
- Dermatophytosis (tinea pedis, onychomycosis)
- Bacterial infections with Escherichia coli, Streptococcus, Mycobacterium tuberculosis
- Viruses, such as Epstein-Barr virus, varicella zoster virus, HIV, molluscum contagiosum
- Ingestion of foods such as blue cheese or tomatoes
- Internal malignancy (breast, lung, lymphoma, leukemia, prostate) (so-called “PEACE”: Paraneoplastic EAC Eruption) (2)
- Other mechanisms proposed to induce EAC include an alteration in the immune landscape secondary to an elevation of proinflammatory cytokines and tumor necrosis factor-α.
- Parasites, such as Ascaris lumbricoides and Phthirus pubis
Avoid known triggers.
Commonly Associated Conditions
- Tinea pedis and other dermatophytoses (common)
- Reports of EAC have occurred in patients with internal malignancy (variable), such as Hodgkin lymphoma (common), chronic lymphocytic leukemia, and breast carcinoma; a wide range of systemic diseases, such as Sjögren syndrome, sarcoidosis, hypereosinophilic syndrome, osteoarthritis, pregnancy, Graves disease, liver or gallbladder disease, appendicitis, Crohn, and lupus
- Infections with M. tuberculosis, syphilis, herpes zoster virus, Epstein-Barr virus, molluscum contagiosum, and HIV have also been associated with EAC.
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