- A rare skin condition in which there is collagen degeneration with granulomatous response, thickened blood vessels and deposition of fat.
- Cause unknown but more often occurs in, or precedes, the development of diabetes.
- More common in women.
- May occur at any age but commonly around 30 years.
- Initial small, well-circumscribed papules or nodules spread to form reddish/brown plaques that become waxy and atrophic.
- Telangiectases on surface.
- Usually occur on pretibial area. Often bilateral.
- Lesions sometimes ulcerate and/or may become infected.
- Check urine for glucose in patients without diabetes and perform further checks in case it develops later.
- Protect legs from trauma, with support stockings to reduce risk of ulceration.
- Tends to run chronic course; poor response to treatment.
- Early lesions may be helped by topical or intralesional steroids to active borders.
- Combined aspirin and dipyridamole.
- Photochemotherapy - psoralen with UVA (PUVA).
Granuloma Annulare (GA)
- Common skin condition; no cause has been found but possible genetic link.
- Sometimes linked with type 1 diabetes. Rarely linked with type 2 diabetes.
- May occur at any age but most commonly occurs in children and young adults.
- May occur anywhere on skin. Usually no symptoms.
- Localised GA: tends to occur over joints such as knuckles, back of hands, elbows or foot. Groups of small papules, erythematous or flesh-coloured, often annular pattern.
- Generalised GA: widespread small flesh-coloured erythematous or mauve papules coalesce, forming plaques that gradually enlarge. More likely to be associated with diabetes.
- Perforating GA: Multiple small pink or reddish papules at any site. May become pustular and exude clear or creamy fluid. Larger ulcerated plaques can develop.
- Usually a clinical diagnosis, but this can be confirmed by biopsy if necessary.
- May resolve spontaneously within a few months, especially localised GA. Response to treatment unreliable.
- Some may persist for years. Generalised GA tends to be more persistent.
- If necessary can be helped by potent topical or intralesional steroid, imiquimod, tacrolimus or pimecrolimus.
- Cryotherapy may improve small plaques.
- Isotretinoin or PUVA.