Follicular borreliosis: an atypical presentation of erythema chronicum migrans.

Lyme serology was positive for both IgG and IgM (ELISA, Enzygnost Borreliosis , Siemens, Dade Behring, Germany, and blot, Euroline WB , Euroimmun, Germany). A punch biopsy of a papule showed a dermal perifollicular ( fig. 2 ) – and occasionnally perineural – infiltrate of lymphocytes and plasma cells, consistent with a borrelial infection. Borrelia burgdorferi DNA was amplified from fresh tissue obtained from a skin biopsy performed on a peripilar papule, using a specific real-time PCR according to Mäkinen et al. [1] (culture not performed). The erythema resolved after a 3-week doxycycline treatment whereas arthralgia and dysesthesia persisted. Erythema chronicum migrans (ECM) is usually the earliest manifestation of Lyme borreliosis. It occurs a few days, sometimes a few weeks, after the tick bite. Lyme disease is caused by an infection with the spirochete B. burgdorferi, which is transmitted by ixodid ticks. ECM usually begins as a macule or papule at the site of the tick bite and evolves as a centrifugally growing annular erythematous plaque with central clearing. It is usually asymptomatic, but localized pruritus, pain, hyperesthesia or dysesthesia have occasionally been reported [2] . It spontaneously disappears within several weeks, occasionally several months; antibiotherapy shortens the evolution and prevents secondary dissemination which can cause neurological, rheumatological, cardiac, ophthalmological and late cutaneous complications [3] . Posttreatment assessment is clinical [4] . Numerous atypical presentations have been described for ECM: mini erythema migrans [5] , erythema with no central clearing, erythema with central induration [6] , vesicles [7] , ulceration, necrosis or purpura [1] , alternating bands of erythema, confluent red or red-blue lesion without central clearing, and even triangular, rectangular or linear lesion [6, 8] .