[Generalized granuloma annulare: A clinicopathological study]

Granuloma annulare (GA) is a benign granulomatous skin disorder that is generalized (GGA) in 15 % of cases. Although many case reports describe a relationship between GGA and systemic diseases, few large series have been published, and their association is debated. We present herein a series of GGA in order to describe their clinical and histological features.

We included all biopsy-proven cases of GA presenting at the dermatopathology laboratory of Strasbourg where generalized (i.e. over 10 lesions). Clinical features were obtained from patients' medical files.

We included 35 GGA, with a sex ratio of 0.5. The mean age was 54 years. Lesions were annular or non-annular in equal measure and were symptomatic in 25 % of cases. Most patients (77 %) had an associated disease, already known in 60 % of cases, including dyslipidemia (27 %), diabetes mellitus (20 %), immunosuppressive drugs (17 %), atopy (17 %), auto-immune disease (17 %), hematological disease (14 %), and cancer (9 %). Histological analysis revealed the predominant pattern to be interstitial (54 %) rather than palisading (20 %), having no correlation with clinical type. Eosinophils were frequent (46 %) in GA but were not correlated with systemic disease or drug taking. Among the 40 % of patients treated, 50 % had a successful outcome on topical corticosteroids, doxycycline, antimalarial drugs or phototherapy.

GGA differs from localized GA, which is mostly associated with an already known systemic disease, whether metabolic, infectious or neoplastic, uncorrelated with clinical or histological features, and screening is necessary.