Granuloma annulare

Gra­nu­lo­ma annu­la­re is a benign inflamm­a­to­ry skin chan­ge with papu­les arran­ged in a ring. It occurs pre­fe­ren­ti­al­ly on the backs of the hands and feet and over joints. Child­ren and young adults are most fre­quent­ly affected.

Cau­ses

The exact cau­se is unknown. An exces­si­ve reac­tion of the immu­ne sys­tem in the con­nec­ti­ve tis­sue is assu­med. Pos­si­ble trig­gers include minor inju­ries, insect bites, infec­tions and vac­ci­na­ti­ons; in exten­si­ve forms, dia­be­tes mel­li­tus should be ruled out.

Sym­ptoms

Typi­cal are skin-colou­red to red­dish, firm papu­les arran­ged in a ring with a flat­ten­ed cent­re. The sur­face is smooth and does not sca­le, which allows it to be distin­gu­is­hed from a fun­gal infec­tion. The­re are usual­ly no sym­ptoms, occa­sio­nal­ly mild itching.

Tre­at­ment

In many cases the lesi­ons resol­ve on their own within one to two years, so a wait-and-see approach is often jus­ti­fied. If requi­red, anti-inflamm­a­to­ry creams, injec­tions or cryo­the­ra­py are opti­ons. Exten­si­ve forms respond in part to phototherapy.