Cutaneous larva migrans
The serpiginous, erythematous raised tracts with bulla formation are clinically diagnostic of cutaneous larva migrans.
This is the infection of the skin with the hookworm parasite of dogs and cats, Ancylostoma braziliense.
Eggs in animal faeces hatch and mature in the soil and are able to invade human skin. The larva cannot complete it’s lifecycle in a human host and it meanders in the skin before dieing.