Erythema annulare centrifugum

1688

Represents a reactive process or antigenic hypersensitivity reaction.

Often idiopathic, but has been associated with dermatophytosis.

A descriptive term for a skin lesion consisting of redness in a ring form that spreads from the center.

Can occur at any age.

Lesions appear as raised pink-red ring or bulls-eye marks.

They range in size from 0.5–8 cm.

The lesions sometimes increase size and spread, may not be complete rings but irregular shapes.

Usually on the thighs and legs but can also appear on the upper extremities, areas not exposed to sunlight, trunk or face.

Not known to be contagious.

No specific tests.

Differential diagnoses: pityriasis rosea, tinea corporis, psoriasis, nummular eczema, atopic dermatitis, drug reaction, erythema migrans and other rashes.

Often no specific cause.

Sometimes linked to underlying diseases and conditions such as ingestion of blue cheese or tomatoes, contact dermatitis, infections such as sinusitis, tuberculosis, candidiasis or tinea, drugs including finasteride, chloroquine, hydroxychloroquine, estrogen, penicillin and amitriptyline, lupus, pregnancy, hormone exposure, and Lyme disease.

Lesions usually resolve in months to years.

The lesions may last from anywhere between 4 weeks to 34 years with an average duration of 11 months.

Treating and removing the disease or malignancy associated with the process will stop the lesions.

Usually does not require treatment, but topical corticosteroids may be helpful.

Lesions are photosensitive they can be reduced with appropriate sunlight.

Topical calcipotriol, a topical vitamin D derivative has been known to be beneficial.

Rare process estimated to affect 1 in 100,000 per year.

Occurs at all ages and all genders equally.

Has been associated with infectious agents, such as Candida albicans, Phthirus pubis, and Escherichia coli, and ingestion of molds, tomatoes, and medications, long-standing diseases; and malignancy.

The incidence is highest during the fifth decade of life.

Can occur at any age.

There is no gender predilection.

The lesions begin as pink papules that grow 2 to 3 mm per day and then develop a central clearing.

Scale on the inner border of the annular erythema is characteristic.

The lesions are minimally elevated and typically lack crusts or vesicles.

The rash generally affects the trunk, buttocks, and proximal extremities and spares the mucous membranes.

Often self-limited, although it can be a chronic and relapsing disease.

Treatment of the underlying condition, if present.

Some use antifungal agents as empirical treatment.

Topical and oral corticosteroids may be used.

Oral antihistamines for pruritus should be considered.

Other agents for treatment include interferon-α, dapsone, etanercept, and metronidazole.