What is the likely cause of lesions observed on a dog's ventral and dorsal surfaces when the dog has been housed outdoors?

The likely cause of lesions observed on a dog's ventral and dorsal surfaces when the dog has been housed outdoors is hookworm infection. Hookworms are intestinal parasites that can lead to significant dermatological changes, particularly in cases of severe infestation or allergic reactions.

In outdoor environments, dogs are often exposed to the feces of infected animals, which can contain hookworm larvae. As these larvae penetrate the skin, they can cause localized dermatitis and lesions. These lesions may appear as itchy, inflamed areas or can become necrotic if the infection is severe. The distribution on the ventral and dorsal surfaces aligns with what is typically seen in hookworm infections, which can lead to cutaneous larva migrans.

While flea allergy dermatitis is a common condition that can cause lesions, it usually presents with a specific pattern, primarily affecting areas where fleas are likely to bite, rather than uniformly across both dorsal and ventral surfaces. Similarly, demodectic mange typically presents with hair loss and scaling, primarily in localized regions, and is linked to the immune status of the dog rather than environmental exposure. Tick-borne diseases can lead to a variety of systemic symptoms and possibly skin lesions, but they are more associated with systemic signs rather than localized skin changes