It has been observed that current crowding and the position of the ohmic contact can have a significant influence on the electroluminescence of InAs-based mid-infrared light-emitting diodes. The asymmetry in the contact position leads to the appearance of highly directional light emission from the mesa edge and a very strong spectral current tuning behaviour, with a tuning rate as high as 1.0 nm mA(-1) over a tuning range of 180 nm. This effect is due to the current crowding near the edge of the mesa resulting in localized optical gain near the mesa boundary.