Final answer:
A flat, nonpalpable lesion that is less than 1 cm in diameter is a macule, which is a smooth spot of discoloration on the skin. Other lesions include papules, which are raised bumps, and bullae, which are fluid-filled and larger than macules.
Step-by-step explanation:
A flat, nonpalpable lesion that is less than 1 cm in diameter is called a macule. Macules are smooth spots of discoloration on the skin that can vary in color but do not present a raised or palpable change to the texture of the skin surface. In contrast, a papule is one of the small raised bumps on the skin that is palpable, and less than 1 cm in diameter. A plaque is a broad, raised area on the skin that is larger than 1 cm. Bullae are fluid- or pus-filled bumps on the skin that are larger than 1 cm, which can present in skin infections such as impetigo. Other types of lesions include pustules, which are pus-producing; vesicles, which are small fluid-filled bumps; and ulcers, which are deeper lesions with loss of the skin surface. It is essential to correctly identify these lesions as they could be indicative of various dermatological conditions or infections like tuberculoid leprosy, caused by a specific microorganism that can be identified in a skin biopsy.