Differential Diagnosis for Ringworm on Chest and Back

• Single most likely diagnosis
  • Tinea corporis (ringworm): This is the most likely diagnosis given the presentation of ringworm all over the chest and back. Tinea corporis is a common fungal infection that can affect any part of the body, characterized by circular, itchy, and red lesions.
• Other Likely diagnoses
  • Tinea versicolor: This condition, caused by a yeast infection, can present with multiple patches on the chest and back, although they are typically not as circular or ring-like as those seen in ringworm.
  • Eczema (atopic dermatitis): While not typically presenting with the classic ring shape, eczema can cause widespread itchy lesions on the chest and back, and its appearance can sometimes be confused with fungal infections.
  • Psoriasis: This chronic skin condition can cause red, scaly patches on various parts of the body, including the chest and back, though the lesions are usually more plaque-like than ring-shaped.
• Do Not Miss diagnoses
  • Syphilis (secondary stage): This sexually transmitted infection can cause a wide range of skin manifestations, including a rash on the chest and back. Although less common, missing syphilis can have serious health implications.
  • Lyme disease: Caused by a tick bite, Lyme disease can present with a distinctive "bull's-eye" rash (erythema migrans), which could be confused with ringworm in some cases. Given the potential for serious complications if untreated, it's crucial not to miss this diagnosis.
• Rare diagnoses
  • Granuloma annulare: A rare skin condition that can cause ring-shaped lesions, although they are typically smaller and less itchy than those seen in ringworm.
  • Erythema annulare centrifugum: A condition characterized by ring-shaped eruptions that are often itchy and can appear on the trunk, though it is relatively rare and often associated with underlying systemic diseases or infections.