Impetigo: A common and highly contagious skin infection that often presents with scabbing, dime-sized lesions, typically caused by Staphylococcus aureus or Streptococcus pyogenes. The appearance and contagious nature make it a prime candidate for this presentation.

Eczema (Atopic Dermatitis): Characterized by itchy, inflamed skin, which can lead to excoriations and scabbing due to scratching. The lesions can vary in size, including dime-sized areas.
Insect Bites: Repeated scratching of insect bites can lead to excoriation and scabbing. The size of the lesions can match the description, depending on the insect and individual reaction.
Contact Dermatitis: An allergic or irritant reaction to substances coming into contact with the skin, leading to inflammation, which can result in scabbing lesions if scratched.

Malignancy (e.g., Basal Cell Carcinoma, Squamous Cell Carcinoma): Although less common, skin cancers can initially present as non-healing lesions or sores. It's crucial to consider this diagnosis, especially in sun-exposed areas or in individuals with risk factors.
Infections like MRSA: Methicillin-resistant Staphylococcus aureus can cause skin lesions that resemble impetigo but require different treatment due to antibiotic resistance.
Lyme Disease: The initial stage of Lyme disease can present with a single lesion known as erythema migrans, which can sometimes be mistaken for other skin conditions. Although not typically dime-sized and scabbing, it's a critical diagnosis not to miss due to its implications.

Pyoderma Gangrenosum: A rare skin condition that leads to painful ulcers, which can start as pustules or insect bite-like lesions and progress. It's more common in individuals with underlying systemic diseases.
Cutaneous Leishmaniasis: Caused by a parasite transmitted by sandflies, leading to skin lesions that can ulcerate and scab. This diagnosis is more relevant in travelers to endemic areas.
Dermatitis Herpetiformis: An autoimmune blistering disorder associated with celiac disease, characterized by intensely itchy, blistering skin. The blisters can evolve into scabbing lesions.