Final answer:
An annular lesion with a red border is characteristic of ringworm, or tinea corporis, which is a fungal infection of the skin. It can be identified through clinical examination and confirmed using a Wood's lamp, which causes the lesion to fluoresce. Ringworm is treated with antifungal medications.
Step-by-step explanation:
An annular lesion with a red border is often indicative of ringworm, which is a common fungal infection of the skin. The condition presents as a distinctly circular rash with a reddish raised edge, and the center may seem normal or exhibit signs of healing. When Sarah's skin lesion was examined under a Wood's lamp, the resulting fluorescence confirmed ringworm, known medically as tinea corporis.
Ringworm can be confused with other skin conditions, but the annular shape and annular presentation with clear edges are characteristic of a fungal infection. It is important to distinguish it from other conditions such as erythema migrans, which presents as a slowly expanding rash that can sometimes clear in the center and is associated with Lyme disease.
Proper diagnosis and treatment are essential for conditions presenting with annular lesions. Ringworm is generally treated with antifungal medications. In Sarah's case, identification through the use of a Wood's lamp helped to expedite the diagnostic process, allowing for prompt treatment initiation.