Confluent annular lesion on the dorsum of the hand

More recently however, a small case-control study failed to reveal any significant correlation between the 2.⁵ At this time, there is no indication to screen for diabetes in an otherwise asymptomatic patient.

FIGURE 2
Generalized granuloma annulare

Differential Dx includes ringworm, Lyme disease

Localized granuloma annulare must be differentiated from the most common annular lesion, tinea corporis, as well as other annular lesions, including necrobiosis lipoidica and erythema migrans.

• Tinea corporis, or ringworm, is a superficial fungal infection of the skin. Similar to granuloma annulare, patients present with a gradually enlarging annular, well-demarcated papular lesion. Ringworm can be distinguished from granuloma annulare by noting the presence of scale, and by performing a potassium hydroxide slide preparation, which would reveal septate hyphae.
• Necrobiosis lipoidica classically presents as annular violaceous plaques on the anterior legs, but may appear on the arms, hands, feet, or scalp. As the lesion expands, the advancing border becomes red and the central area typically develops a waxy yellow surface, with prominent telangiectasias. This lesion is generally flat or atrophic, and does not have the same raised border as is seen in granuloma annulare.
• Erythema migrans is the characteristic rash of early localized Lyme disease. This classic “bull’s-eye” rash is an annular lesion with concentric redness and expanding central clearing. Erythema migrans typically appears 7 to 10 days after a patient has been bitten by an infected tick. The classic red lesion starts as a small papule at the site of inoculation, while the expanding ring remains flat and lacks the papular appearance of granuloma annulare.

While uncommon, cutaneous sarcoidosis should also be considered in the differential diagnosis. Cutaneous manifestations occur in up to 20% of patients with sarcoidosis.² The most common presentation is a maculopapular eruption involving the face. Lesions may also be nodular or plaque-like. Biopsy is necessary for diagnosis.