[Reactive arthritis and infestation by Giardia lamblia].

The association between reactive arthritis and Giardia lamblia infestation, although it has been previously described, is not very common. We present a 32 year-old woman who had oligo-arthritis and erythema nodosum after Giardia lamblia infestation. We think that a Giardiasis should be more frequently considered in patients with arthritis after an episode of diarrhea.