Author: Dr Maneka Gnanasegaram, Dermatology Registrar, Christchurch, New Zealand, 2010.
What is actinic granuloma?
Actinic granuloma is an uncommon skin disease that presents with asymptomatic annular (ring-shaped) plaques on sun-exposed sites.
It occurs most often in fair skinned middle-aged women living in sunny climates. There is debate around whether it is a distinct entity or a variant of granuloma annulare.
It is also known as O'Brien granuloma after the physician that first described it.
What is the cause of actinic granuloma?
Actinic granuloma is thought to be inflammatory response to sun damage, possibly to injured elastic fibres. The white cells known as Helper T-lymphocytes are predominantly involved.
What are the clinical features of actinic granuloma?
Actinic granuloma begins as flesh-coloured or pink papules (small bumps) which coalescence into annularplaques (larger thickened patches) ranging in size from 1 to 10 cm in diameter. The plaques typically have raised red borders and a slightly thinned, pale central area.
The lesions do not usually result in symptoms, but when exposed to the skin they may become red and uncomfortable.