Granuloma Annulare at a Glance
- Relatively common disorder; exact prevalence is unknown; favors 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 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 cases resolve spontaneously within 2 years.
Granuloma annulare is a benign self-limited disease, first described by Colcott-Fox1 in 1895 and Radcliffe-Crocker2 in 1902.
Granuloma annulare is a relatively common disorder.3 It occurs in all age groups, but is rare in infancy.3–5 The localized annular and subcutaneous forms occur more frequently in children and young adults. The generalized variant is more common in adults. Many studies report a female preponderance,3 but some have found a higher frequency in males.6 Granuloma annulare does not favor a particular race or geographic area, with the possible exception of the perforating type, which may be more common in Hawaii.7
Most cases of granuloma annulare are sporadic. Occasional familial cases are described with occurrence in twins, siblings, and members of successive generations.3,8,9 Attempts to identify an associated HLA subtype have yielded disparate results in different population groups.10,11
The etiology of granuloma annulare is unknown, and the pathogenesis is poorly understood. Most cases occur in otherwise healthy children. A variety of predisposing events and associated systemic diseases is reported, but their significance is unclear. It is possible that granuloma annulare represents a phenotypic reaction pattern with many different initiating factors.12
Nonspecific mild trauma is considered a possible triggering factor because of the frequent location of lesions on the distal extremities of children. An early study of subcutaneous granuloma annulare found a history of trauma in 25% of children,3 but this observation has not been replicated. Trauma is also a suspected factor in auricular lesions.13 Granuloma annulare has occurred after a bee sting,14 a cat bite,15 and an octopus bite,16 and insect bite reactions have also been implicated.3 There is a report of perforating granuloma annulare in long-standing tattoos.17 Widespread lesions have developed after waxing-induced pseudofolliculitis18 and erythema multiforme minor,19 and in association with systemic sarcoidosis.3,20 Severe uveitis without other evidence of sarcoidosis has occurred in a few patients with granuloma annulare.21,22,23
Infections and Immunizations
There are several reports of the development of granuloma annulare within herpes zoster scars, sometimes many years after the active infection.24 It is also described after chickenpox.25 Generalized, localized, and perforating forms of granuloma annulare may occur in association with ...