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AT-A-GLANCE
Granuloma annulare is a relatively common disorder. The exact prevalence is unknown, but it occurs more often in children and young adults.
A localized ring of beaded papules on the extremities is typical; generalized, subcutaneous, perforating, and patch subtypes also occur.
The cause of granuloma annulare is unknown, and the pathogenesis is poorly understood.
Pathologic features consist of granulomatous inflammation in a palisaded or interstitial pattern associated with varying degrees of connective tissue degeneration and mucin deposition.
Most localized cases resolve spontaneously within 2 years.
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Granuloma annulare is a benign self-limited disease that was first described by Colcott-Fox in 1895 and Radcliffe-Crocker1 in 1902.
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Granuloma annulare is a relatively common disorder.2 It occurs in all age groups but is rare in infancy.2-4 The localized annular and subcutaneous forms occur more frequently in children and young adults. The generalized or disseminated variant is more common in adults. Many studies report a female preponderance,2 but some have found a higher frequency in males.5 Granuloma annulare does not favor a particular race or geographic area.
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Most cases of granuloma annulare are sporadic. Occasional familial cases are described with occurrence in twins, siblings, and members of successive generations.2,6,7 Attempts to identify an associated human leukocyte antigen subtype have yielded disparate results in different population groups.
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The typical history is of one or more papules with centrifugal enlargement and central clearing. These annular lesions are often misdiagnosed as tinea corporis and treated unsuccessfully with topical antifungal agents. Subcutaneous nodules may raise suspicion about malignancy or rheumatoid disease.
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Granuloma annulare is usually asymptomatic. Mild pruritus may be present, but painful lesions are rare. Nodular lesions on the feet may cause discomfort from footwear. Cosmesis is often a concern for adolescent and adult patients, particularly with generalized disease.
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Clinical variants of granuloma annulare include the localized, generalized, subcutaneous, perforating, and patch types. Linear granuloma annulare, a follicular pustular form, papular umbilicated lesions in children, and giant plaques have also been described. There is overlap among the different variants, and more than one morphologic type may coexist in the same patient.
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The most common form of granuloma annulare is an annular or arcuate lesion. It may be skin colored, erythematous, or violaceous. It usually measures 1 to 5 cm in diameter.2 The annular margin is firm to palpation and may be continuous or consist of discrete or coalescent papules in a complete or partial circle (Fig. 34-1). The epidermis is usually normal, but surface markings may be attenuated over individual papules. Within the annular ring, the skin may have a violaceous ...