Granuloma anulare classic type L92.0

Asymptomatic, chronic, necrobiotic, granulomatous inflammation of the skin, with formation of skin-coloured or slightly reddened papules and plaques that form characteristic anular structures.

Pathogenesis unclear. A late type reaction involving cell-mediated immune processes is suspected.

It occurs after insect bites or other local trauma, in the context of infections (association with viral infections, e.g. Epstein-Barr virus, HIV, herpes zoster virus and SARS-CoV-2), autoimmune diseases of the thyroid gland, frequently in diabetes mellitus.

There is good casuistic evidence for drug-induced granuloma anulare. The following drugs were listed (cited n. Boyoung Lee S): Adalimumab (n=5), allopuriol (n=3); gold (n=2), infliximab (n=2), topiramate (n=2), amlodipine, calcitonin, diclofenac, etanercept, interferon alpha, paroxetine, thalidomide, phostal stalergenes; vemurafib (n=1 each) .

Of historical and pathogenetic interest is the occurrence of granuloma anulare with vitamin D3 therapy(granuloma anulare vigantolicum) in tuberculosis.

In former times often associated with tuberculosis. Possibly genetic predisposition.

Occurs mainly in children and adolescents, preference for the female sex.

In the classic and most common granuloma anulare, there is a solitary, or a few, circular or ring-shaped, completely asymptomatic ornaments that can reach a diameter of 1.0 to 3.0 cm. The ring or circular ornaments are composed of smaller, approximately 0.1-0.3 cm, aggregated, firm, red or skin-colored, surface-smooth nodules and plaques. In most cases, the composite nodule structure is still evident after prolonged persistence. The growth is slow and can last for many months. If 2 papule circles meet, arcuate ornaments result, which efface each other in places.

Typically, the single efflorescence of granuloma anulare does not exceed a maximum size of 5.0 cm.

In rare cases, however, an extreme extension up to 10.0 cm may occur(granuloma anulare giganteum), without any explanation in individual cases.

Circumscribed nodular sites of inflammation in the upper and middle dermis (rarely located in subcutaneous fatty tissue) with central necrobiosis and throughput with nuclear fragments. Characteristic is an enclosing palisade granuloma of lymphocytes, macrophages (histiocytes), fibroblasts and, more rarely, multinuclear giant cells. Occasionally also admixtures of eosinophilic leukocytes and plasma cells. Rarely vasculitic changes can be detected with leukocytoclasia. In the granuloma anulare of the interstitial type, less nodular but rather diffuse interstitial infiltrates of CD68-positive histiocytes and lymphocytes around alcian blue-positive mucin deposits in the reticular dermis are observed.

Necrobiosis lipoidica (when localized on the lower extremity): telangiectasia, sunken speckly shiny centre, mainly localized on the extensor lower legs.

Sarcoidosis: mainly in cool skin areas such as the face; typical diascopically detectable intrinsic infiltrate.

Rheumatoid nodules: positive rheumatoid factor or ANA.

Syphilid: positive syphilis diagnosis.

Lichen myxoedematosus: mainly on thighs, trunk, extensor sides of arms and back of hands, with dense, whitish to yellowish papules also in linear arrangement. Histology is diagnostic.

Lichen planus anularis: on flexor sides of joints and mucous membrane with typical Wickham's pattern. Histology is diagnostic.

Dermatitis, interstitial, granulomatous with arthritis: very rare, clinical picture has not yet acquired a sharp clinical contour.

• Children: Wait for spontaneous remission, if necessary mask with foil, hydrocolloid foil (e.g. Varihesive extra thin) or adhesive plaster bandage. If necessary, occlusive dressing with topical glucocorticoids (e.g. Ecural Fatty Ointment).
• Adults: Triamcinolone acetonide crystal suspension intralesional (e.g. Volon A 10 mg, 1:3-1:5 diluted with local anaesthetics, e.g. Scandicain), multiple, or occlusive dressing with fluorinated glucocorticoid ointments (e.g. Ultralan ointment). In older, otherwise therapy-resistant foci, cryosurgery with a closed system may be necessary: temperature at the stamp -180/-190 °C, only brief freezing. If necessary, repeat after 10-14 days.

Antimalarial drugs e.g. Hydroxychloroquine Initial 400 mg/day for 4-8 weeks, then 200 mg/day and further reduction depending on the findings.

Alternative: In case of generalised infestation ( Granuloma anulare disseminatum), test with fumaric acid esters e.g. Fumaderm Tbl (well effective; off-label use).

Alternative: Retinoids ( Acitretin) in an initial dosage of 0.5 mg/kgkgkg and a maintenance dose of 0.1-0.2mg/kg/kg.

Alternatively, retinoids in combination with glucocorticoids. Acitretin dose as before; glucocorticoid dose (prednisolone) initial 0.5mg/kg/kgkg, maintenance dose (several months) with 0.05-0.1 mg/kg/kg.

Alternatively, dapsone (DADPS). Initial 100-200 mg/day p.o. with slow dose reduction.

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