Single most likely diagnosis:
- Viral wart: This is the most likely diagnosis given the description of a wart on the finger, as warts are common and caused by the human papillomavirus (HPV).
Other Likely diagnoses:
- Mole or melanocytic nevus for the spot on the back: These are common skin lesions that can appear as spots.
- Seborrheic keratosis for the spot on the back: A benign skin growth that can appear as a spot, especially in older adults.
- Verruca vulgaris (common wart) for the wart on the finger: This is a type of wart caused by HPV, fitting the description.
Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):
- Melanoma for the spot on the back: Although less likely, melanoma is a serious form of skin cancer that can present as a new or changing spot.
- Squamous cell carcinoma or basal cell carcinoma for the spot on the back or wart on the finger: These are types of skin cancer that, although rare in these descriptions, could be deadly if not diagnosed and treated.
Rare diagnoses:
- Dermatofibroma for the spot on the back: A benign skin growth that can appear after a minor injury, less common than other diagnoses.
- Epidermoid cyst for the spot on the back: A benign cyst that can appear as a spot, less likely than other diagnoses.
- Verrucous carcinoma for the wart on the finger: A rare, low-grade malignancy that can resemble a wart, important to distinguish from a benign wart.