Tinea corporis (Ringworm): This is the most common diagnosis for round itchy lesions with central clearing. It's a fungal infection of the skin, caused by dermatophytes, which typically presents with annular (ring-shaped) lesions that have a clear center.

Nummular dermatitis: Also known as discoid eczema, this condition presents with coin-shaped lesions that are itchy and can have central clearing. It's often associated with dry skin and can be triggered by various factors including allergies and irritants.
Granuloma annulare: A benign skin condition characterized by ring-shaped lesions, often with central clearing. It's more common in children and young adults, and the exact cause is unknown.
Pityriasis rosea: Although not always round, the lesions of pityriasis rosea can sometimes appear as such and may have central clearing. It typically starts with a herald patch, followed by a wider rash.

Lyme disease (Erythema migrans): The initial lesion of Lyme disease, known as erythema migrans, can appear as a round, itchy lesion with central clearing. It's crucial to consider this diagnosis, especially in individuals who have been exposed to ticks, as untreated Lyme disease can lead to serious complications.
Cutaneous T-cell lymphoma (Mycosis fungoides): In its early stages, mycosis fungoides can present with patches or plaques that might resemble round itchy lesions with central clearing. Given its potential for severe outcomes if left untreated, it's essential to include it in the differential diagnosis.

Erythema annulare centrifugum: A rare condition characterized by annular (ring-shaped) lesions that migrate outward. It can be associated with various underlying conditions, including infections and malignancies.
Subacute cutaneous lupus erythematosus: A subtype of lupus that can present with annular lesions, although these are not always itchy and may not consistently have central clearing. It's an important consideration due to its association with systemic lupus erythematosus.