Differential Diagnosis for Annular Rash with Distinct Borders and Scaly Center
- Single most likely diagnosis
- Tinea corporis (Ringworm): This is the most likely diagnosis due to the characteristic annular shape with distinct borders and a scaly center. It's a common fungal infection that can occur on various parts of the body.
- Other Likely diagnoses
- Granuloma annulare: A benign skin condition characterized by a ring-shaped lesion with a scaly center, although it tends to be more papular and less scaly than tinea corporis.
- Nummular dermatitis: A type of eczema that can present with coin-shaped lesions, which might resemble an annular rash, especially if the lesions merge.
- Psoriasis (annular type): Although less common, psoriasis can present in an annular pattern with scaly plaques, particularly on the trunk or limbs.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Lyme disease (Erythema migrans): The initial stage of Lyme disease can present with an expanding annular rash, which is crucial to diagnose early due to the potential for severe neurological and cardiac complications if left untreated.
- Leishmaniasis: In some cases, cutaneous leishmaniasis can present with annular lesions, and missing this diagnosis could lead to significant morbidity, especially in endemic areas.
- Rare diagnoses
- Erythema annulare centrifugum: A rare condition characterized by annular erythematous lesions that can be scaly, often associated with underlying conditions such as infections or malignancies.
- Subacute cutaneous lupus erythematosus: A variant of lupus that can present with annular polycyclic lesions, which, although rare, is important to consider due to its systemic implications.