Tinea corporis (Ringworm): This is the most likely diagnosis given the patient's symptoms and history of handling dogs. Tinea corporis is a dermatophyte infection that can be spread by direct contact with infected animals, and it typically presents with itchy, round, coin-sized lesions.

Contact dermatitis: This could be a possible diagnosis if the patient has developed an allergic reaction to something related to her job, such as dog shampoo or flea medication.
Eczema (atopic dermatitis): This is a common skin condition that can cause itchy, round lesions, although it is not typically associated with handling animals.
Pityriasis rosea: This is a skin condition that can cause itchy, round lesions, although it is not typically associated with handling animals and usually has a distinctive "herald patch" preceding the outbreak.

Lyme disease: Although less likely, Lyme disease can cause a distinctive "bull's-eye" rash (erythema migrans) that could be mistaken for a dermatophyte infection. Given the potential seriousness of Lyme disease, it is essential to consider this diagnosis, especially if the patient has been exposed to ticks.
Leptospirosis: This bacterial infection can be spread through contact with infected animal urine and can cause a range of symptoms, including skin lesions. Although rare, it is a potentially serious condition that should not be missed.

Sporotrichosis: This is a rare fungal infection that can be spread through contact with infected soil or plants. It typically causes lesions on the skin, but it is less likely given the patient's symptoms and history.
Dermatophytid reaction: This is a rare condition that occurs in response to a dermatophyte infection elsewhere on the body, causing lesions at a distance from the primary infection site.