Thermosensitive lichen amyloidosis

Abstract

A 26-year-old male presented with a 3-year history of lichen amyloidosis. On examination, there was a pigmented papular eruption with a ripple pattern affecting the limbs and trunk but sparing the axillae, antecubital and popliteal fossae, central chest, neck and face. There was also prominent sparing of the skin overlying the superficial veins of the limbs. The sparing of the superficial veins of the limbs by lichen amyloidosis raised the possible role of cutaneous temperature in governing the distribution of amyloid deposits in our patient.Total body infrared thermography demonstrated consistent sparing of the amyloid deposits in areas with higher cutaneous temperatures such as the neck and axillae as well as the course of the superficial veins. The cooler areas such as the extensor surfaces of the arms and legs corresponded to areas of amyloid deposition. Narrow band ultraviolet B (NBUVB) phototherapy over a 5-month period resulted in a marked improvement of pruritus and clearing of the amyloid deposits.Our patient clearly demonstrated lichen amyloidosis in a thermosensitive distribution. This may be a gross manifestation of previous reports of in vitro thermosensitivity of amyloid fibril formation and may have potential implications in treatment at least in a subset of patients demonstrating this clinical feature.