Differential Diagnosis for a Suspicious Skin Lesion
Single Most Likely Diagnosis
- Cellulitis: This is the most likely diagnosis given the symptoms of redness, swelling, and pain. Cellulitis is a common bacterial skin infection that can cause these symptoms, especially if the skin lesion has become infected.
Other Likely Diagnoses
- Infected Melanoma or Skin Cancer: A pre-existing skin lesion that becomes infected can present with similar symptoms. It's crucial to consider the possibility of an underlying malignancy, especially if the lesion has changed in size, shape, or color.
- Abscess: An abscess is a collection of pus that can form in the skin, often causing redness, swelling, and pain. It could be related to the skin lesion if the lesion has become infected and formed a pocket of pus.
- Erysipelas: This is a type of skin infection that affects the upper layer of the skin, often causing redness, swelling, and pain. It can be distinguished from cellulitis by its well-defined borders and is typically more superficial.
Do Not Miss Diagnoses
- Necrotizing Fasciitis: Although rare, this is a life-threatening condition that requires immediate medical attention. It's characterized by necrosis of the fascia and can present with severe pain, swelling, and redness, often with a history of trauma or infection.
- Methicillin-Resistant Staphylococcus aureus (MRSA) Infection: MRSA infections can cause severe skin and soft tissue infections, including abscesses and cellulitis. It's essential to consider MRSA in the differential diagnosis, especially in patients with risk factors such as recent hospitalization or antibiotic use.
- Lymphoma or Leukemia Cutis: In rare cases, skin lesions can be a manifestation of systemic diseases like lymphoma or leukemia. These conditions can cause skin lesions that become infected or inflamed, presenting with similar symptoms.
Rare Diagnoses
- Erythema Migrans (Lyme Disease): This is the characteristic rash of Lyme disease, caused by the bite of an infected tick. It can present as a red, expanding rash that may be painful but is typically not as swollen as cellulitis.
- Sweet Syndrome (Acute Febrile Neutrophilic Dermatosis): A rare condition characterized by fever, neutrophilia, and tender, erythematous skin lesions. It can be associated with infections, inflammatory diseases, or malignancies.
- Pyoderma Gangrenosum: A rare skin condition that causes painful ulcers, often with a history of trauma or underlying systemic disease. It can present with redness, swelling, and pain, but the presence of an ulcer is a distinguishing feature.