Contact Dermatitis: This is a common condition in children, often caused by an allergic reaction or irritation from substances like poison ivy, oak, or sumac, or from certain metals, soaps, or detergents. The distribution on the foot, wrist, and arm could be consistent with exposure to an allergen or irritant.

Impetigo: A contagious bacterial skin infection that can cause blisters, especially on exposed areas like the face, arms, and legs, but can spread to other areas through touch or contaminated items.
Eczema (Atopic Dermatitis): While more commonly associated with dry, itchy skin, certain types of eczema can cause blistering, particularly dyshidrotic eczema on the hands and feet.
Viral Exanthems: Various viral infections can cause rashes, some of which may blister. The location and pattern can vary widely depending on the virus.

Staphylococcal Scalded Skin Syndrome (SSSS): A serious condition caused by staphylococcal toxins that can lead to widespread blistering and peeling of the skin. It's more common in infants and young children and requires prompt medical attention.
Toxic Epidermal Necrolysis (TEN) and Stevens-Johnson Syndrome (SJS): These are severe skin conditions usually triggered by medications. They can cause blistering of the skin and mucous membranes and are medical emergencies.
Child Abuse: In some cases, burns or other injuries might be inflicted on a child, presenting as blistering rashes. It's crucial to consider this possibility, especially if the pattern of injury is suspicious or if there are inconsistencies in the history provided.

Pemphigus: A group of rare skin disorders that cause blistering of the skin and mucous membranes. It's more common in adults but can occur in children.
Epidermolysis Bullosa: A genetic condition that results in fragile skin and blisters, often from minor trauma or even spontaneously.
Bullous Pemphigoid: An autoimmune disease that causes blistering skin lesions, more commonly seen in older adults but can rarely occur in children.