Differential Diagnosis for Circular Patch Rash
- Single most likely diagnosis
- Tinea corporis (ringworm): This is a common fungal infection that typically presents with a circular, itchy, and scaly rash. The rash often has a clear center, giving it a ring-like appearance.
- Other Likely diagnoses
- Eczema (nummular dermatitis): This condition can cause circular patches of dry, itchy skin, often due to dry skin or allergic reactions.
- Psoriasis: While psoriasis is more commonly associated with plaque-like lesions, it can also present with circular patches, especially in the guttate form.
- Pityriasis rosea: This condition starts with a single, large patch (herald patch), followed by smaller, circular patches of skin lesions, often on the trunk.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Lyme disease: The initial stage of Lyme disease can present with a circular, expanding rash (erythema migrans), which is a critical diagnosis to make due to the potential for serious complications if left untreated.
- Erythema multiforme: This is an immune-mediated condition that can cause target-like lesions, which might appear circular. It can be associated with infections or medications and can have severe forms.
- Rare diagnoses
- Granuloma annulare: A rare condition characterized by circular patches of small, bumps or lesions, often on the hands and feet.
- Sarcoidosis: While more commonly associated with lung and lymph node involvement, sarcoidosis can also cause skin lesions, including circular patches.
- Leprosy: In its early stages, leprosy can cause light-colored or hypopigmented patches, which might appear circular. This diagnosis is crucial due to the potential for nerve damage and disability if not treated promptly.