Differential Diagnosis for Lower Leg Rash
Single Most Likely Diagnosis
- Eczema (Dermatitis): This is a common condition that can cause a rash on the lower leg, often due to dry skin, irritation, or allergic reactions. The rash is typically itchy, red, and scaly.
Other Likely Diagnoses
- Cellulitis: A bacterial infection of the skin and underlying tissues, characterized by redness, swelling, warmth, and pain. It often occurs on the lower leg and can be caused by streptococcal or staphylococcal bacteria.
- Contact Dermatitis: An allergic or irritant reaction to substances that come into contact with the skin, such as soaps, detergents, or plants. This can cause a rash, itching, and blistering on the lower leg.
- Varicose Eczema: A condition associated with varicose veins, characterized by a rash, itching, and skin discoloration on the lower leg.
- Psoriasis: A chronic skin condition that can cause a rash on the lower leg, characterized by thick, scaly, red patches.
Do Not Miss Diagnoses
- Deep Vein Thrombosis (DVT): Although not typically thought of as a rash, DVT can cause skin redness, warmth, and swelling on the lower leg, which may be mistaken for a rash. It is a life-threatening condition that requires prompt medical attention.
- Necrotizing Fasciitis: A rare but deadly bacterial infection that can cause skin redness, swelling, and pain on the lower leg, which may be mistaken for a rash. It requires immediate medical attention.
- Erythema Nodosum: A condition characterized by painful, red nodules on the lower leg, which can be a sign of an underlying infection or inflammatory condition.
Rare Diagnoses
- Lichen Planus: A rare skin condition that can cause a rash on the lower leg, characterized by purplish, itchy, flat bumps.
- Sarcoidosis: A rare condition that can cause skin lesions, including rashes on the lower leg, as well as lung and other organ involvement.
- Cutaneous T-Cell Lymphoma: A rare type of skin cancer that can cause a rash on the lower leg, characterized by red, scaly, or crusted patches.