Acrodermatitis chronica atrophicans: a light and electron microscopic study.

Degeneration of the elastica and collagen fibres in skin biopsies from patients with acrodermatitis chronica atrophicans was studied with light and electron microscopy. Elastic fibres were involved in the infiltrative stage while the elastin plexus was still present. In the atrophic phase, only fragments of elastic and oxytalan fibres were seen and the elaunin plexus was absent. Some collagen fibres were surrounded by osmiophilic material. In all biopsies, myelin sheaths were collapsed without axon structures. Spirochetes could be demonstrated in 69% of the biopsies and were most numerous in infiltrative and nodular lesions. The loss of elasticity of the skin in the atrophic phase may be caused by the destruction of both elastic and elastin fibres.