Granuloma Annulare

Several asymptomatic, erythematous papules and plaques had appeared on the hands of an otherwise healthy 11-year-old girl. The personal and family medical histories were noncontributory. A punch biopsy from the largest lesion on the palm confirmed the clinical diagnosis of localized granuloma annulare, a self-limited inflammation of the dermis.

Lesions of granuloma annulare usually disappear spontaneously within several months to several years. Although the eruption clears in most patients within 2 years, lesions may persist for more than 8 years in up to 25% of those with the disease.

Dr Amor Khachemoune and Mana Ogholikhan of Washington, DC, write that most granuloma annulare lesions occur locally; they can also be subcutaneous, perforating, macular, and disseminated.

The localized disorder presents as solitary or multiple lesions that usually erupt on the lateral or dorsal surface of the fingers or hands, elbows, dorsum of the feet, and ankles. Typically, 2- to 4-mm; skin-colored, violaceous, or brown; flat-topped dermal papules spread peripherally to form 1- to 5-cm annular plaques with distinctive borders and central involution. Vesicles and pustules are absent; scaling may be noted. Ulceration and involvement of mucous membranes are rare. Most of the plaques involute with no residual scarring.

Two thirds of patients with localized granuloma annulare are younger than 30 years; as many as 40% of patients are younger than 15 years.

The subcutaneous form occurs most commonly in children, particularly those between ages 2 and 6 years. Boys are affected twice as often as girls. The lesions are asymptomatic, rapidly growing, soft tissue nodules that are usually firm, nontender, nonmobile, and may enlarge to 1 to 5 cm. They frequently develop on the extremities, particularly on the pretibial region. Many lesions are fixed to the periosteum; however, the overlying epidermis and the underlying bone are clinically normal. Localized dermal lesions are noted in 25% of patients with subcutaneous disease. These lesions are self-limited but can recur.¹

Perforating granuloma annulare is rare. It presents as skin-colored to erythematous, scaly and crusted, umbilicated papules. Lesions tend to improve in the winter and worsen in the summer. Papules of perforating disease evolve more slowly, are more pustular, and are more likely to scar than the lesions of localized disease.²

The flat, slightly palpable lesions of the macular variant tend to arise on the feet, ankles, and thighs. Individual lesions are typically between 1 and 4 cm in diameter but can be much larger. Small papules may be palpated; papules or small annular lesions can be seen when the skin is stretched.

Disseminated disease presents as multiple skin-colored or erythematous papules that can fuse to form annular rings.

The cause of granuloma annulare is unclear; it can occur following viral infections, insect bites, tuberculin skin tests, cell-mediated hypersensitivity reactions, trauma, vitamin D excess, and ultraviolet light exposure. Although the existence of a relationship between granuloma annulare and diabetes is debatable, this skin disease occurs in up to 10% of adults with diabetes.² Iritis, sarcoidosis, autoimmune thyroiditis, and neoplasms are other associated diseases. Results of a complete blood cell count, blood chemistry panel, rheumatoid factor level, and erythrocyte sedimentation rate can help you confirm the diagnosis of an associated disease.

The natural history of granuloma annulare in persons with HIV infection is unknown. However, the skin disorder has developed in patients in all stages of HIV disease.

The differential diagnosis includes tinea, nummular eczema, the herald patch of pityriasis rosea, urticaria, erythema chronicum migrans (Lyme disease), and erythema multiforme. A skin biopsy can confirm the diagnosis. Histologic features are well-demarcated foci of collagenous degeneration. The focal mucinous degeneration of collagen, or necrobiosis, is surrounded by lymphocytes and fibroblasts, often in a palisading pattern. Giant cells are rarely found.

Reassurance and observation are sufficient therapy. To hasten resolution, both intralesional and topical superpotent corticosteroids may be tried; however, limit their use to avoid secondary atrophy, telangiectases, and pigmentary changes. Cryotherapy, lasers, surgical excision, pentoxifylline, oral vitamin E, antimalarials, alkylating agents, various NSAIDs, and radiation therapy also have been used. Psoralen-UV-A therapy, isotretinoin, dapsone, and antituberculosis medications have been used successfully to treat perforating granuloma annulare.³

One case study reported that a lesion rapidly resolved after 2 separate biopsies, whereas the lesions that were not biopsied remained unchanged.⁴ This report raised speculation that biopsy may induce resolution of granuloma annulare.