The sense of touch hinges on tissues transducing stimuli applied to the skin and somatosensory neurons converting mechanical inputs into currents. Like mammalian Pacinian corpuscles, the light-touch response of the prime model organism C. elegans adapts rapidly, and is symmetrically activated by the onset and offset of a step indentation. Here, we propose a quantitative model that combines transduction of stimuli across the skin and subsequent gating of mechanoelectrical channels. For mechanics, we use an elastic model based on geometrically-nonlinear deformations of a pressurized cylindrical shell. For gating, we build upon consequences of the dermal layer’s thinness and tangential stimuli. Our model demonstrates how the onset-offset symmetry arises from the coupling of mechanics and adaptation, and accounts for experimental neural responses to a broad variety of stimuli. Predicted effects of modifications in the mechanics or the internal pressure of the body are tested against mechanical and neurophysiological experiments.