Erythema (Chronicum) Migrans

ICD-11

1C1G.0

Synonyms

Stage 1 Lyme disease; early cutaneous Lyme borreliosis; Erythema migrans.

Epidemiology

In endemic areas in northern, middle and eastern Europe up to 20% of Ixodes ricinus are infected by B.afzelii, B.garinii, B.Spielmanii and Borrelia burgdorferi sensu strictu. In the USA B.burgdorferi sensu strictu is most common. After a tick bite from an infected Ixodes, in 5% a local infection appears and in up to 2%, if not treated, a manifestation of a borreliosis take place. About 100 -200 cases / 100.000 people per year in Germany, in Austria or Slovenia even higher up to 400 cases. Individuals at special risk: farmers, joggers, hikers, dog owners, forest workers.

Definition

Early target like and annular, then centrifugally spreading erythema with a prominent margin.

Aetiology & Pathogenesis

Ixodes inserts (no bite!) hypostoma into the upper dermis. Factors help stabilizing its position and to open vessels and avoiding blood clotting when starting to suck. Because of osmotic balance saliva with borrelia is deposited in the skin. Borrelia organisms are 20 µm long and 3µm thick, multiple antigenic structures (853). Flagellin (endoflagellins up to 12 different structures) and outer surface lipoproteins OspA - G. The innate immune system reacts i.p. on the local site and the regional lymph-node with a strong B-cell production of antibodies. Serological detection usually occurs by the third week after exposure.

Signs & Symptoms

Incubation period: 1-4 weeks.
Skin: sharply bordered erythematous ring with prominent border (sometimes with central hemorrhagic area), spreads peripherally and clears centrally, mostly 10 - 30 cm depending on body site.
Center variable: pale, erythematous, hemorrhagic, vesicular. Multiple annular erythemas possible. Systemic symptoms can also occur: headache, neck pain, arthralgias, fever.

Localisation

Preferentially: knee, lower leg, inguinal and buttocks, lumbar area, axilla, shoulder, chest, neck, auricle, mamilla.

Classification

Stage 1 early localized, stage 2 early disseminated, stage 3 late disseminated.

In stage 1 ,2 and 3 an overlap can occur. ( see also chapter 2.2.10 Acrodermatitis Chronica Atrophicans; 2.2.9 Pseudolymphomas)

Laboratory & other workups

Serology with IgM and IgG and additional early antigen markers in the immunoblot (p41, flagellin, OspE, Osp C ) after about 3 weeks. Late stage Osp 17, A, B, p43.

Dermatopathology

Biopsy from the margin. Superficial dermal lymphocytic infiltrate with perivascular accumulation. Later more perineural and periglandular infiltrates and plasma cells appear. Initially some eosinophils.

Course

See classification. If not treated, dissemination may occur and manifestations in other organ systems take place: joints, muscles, peripheral and central nervous system, heart.

Complications

Meningoradiculitis, Guillain Barré syndrome, arthritis, myocarditis (conduction disturbances), encephalopathy.

Diagnosis

History, clinical features, PCR from lesion: borrelia DNA; borrelia serology initially negative.

Differential diagnosis

Other arthropodes (spider), urticaria, erythema and granuloma annulare, other figurate erythemas incl. fixed drug eruption, tinea, erysipelas and erysipeloid.

Prevention & Therapy

Doxycycline 100 mg b.i.d. for 14 days. Alternatively, Amoxicillin 3 x 500 to 1000 mg/d 2 weeks. Azithomycin 2 x 250 mg / d for 10 days.

2.2.8 Erythema (Chronicum) Migrans