Differential Diagnosis for the Lesion
- Single most likely diagnosis
- Cellulitis: The description of the lesion being red and hot to touch is consistent with cellulitis, a common bacterial skin infection that can cause these symptoms. The absence of a focal area of fluctuance (which would indicate an abscess) supports this diagnosis, as cellulitis is characterized by diffuse inflammation.
- Other Likely diagnoses
- Erysipelas: This is another type of skin infection that can present with redness and warmth, similar to cellulitis. It is typically more superficial and has a well-defined border.
- Staphylococcal infection (such as impetigo or folliculitis): While the question mentions "Staph," which could imply a staphylococcal infection, the description provided does not specifically point towards a localized infection like impetigo or folliculitis without more specific symptoms.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Necrotizing fasciitis: Although less likely, this is a severe infection that can present with similar initial symptoms (redness, warmth) but progresses rapidly and can be fatal if not promptly treated. The absence of fluctuance does not rule out necrotizing fasciitis, as it often involves deeper tissue.
- Gas gangrene: Another severe condition that, while rare, could present with similar symptoms in its early stages. It is characterized by infection with gas-producing bacteria and can rapidly progress.
- Rare diagnoses
- Erythema migrans (Lyme disease): This can cause a red, expanding rash, but it is typically not hot to touch and is associated with other symptoms like fever and headache.
- Sweet syndrome (acute febrile neutrophilic dermatosis): A rare condition characterized by fever, neutrophilia, and tender, erythematous skin lesions. It is not typically associated with bacterial infections but can mimic infectious processes.