It is a skin disease caused due to neuron system. In this disease, the pitta dosha causes eruption of reddish painful boils in the hands, armpit, shoulders, eyes and waist.
bahuparshvvasakakseshu krishnavisphotam savedanam
pitta prakopasambhutam kaksamityaminidirshot
The peculiarity of this disease is that the eruptions occur in a single line resembling the sacred thread (yagyopaveet) hence it has been named Zoster.
...