Differential Diagnosis for Unilateral Lower Leg Swelling Postpartum with Mottling but DVT US Negative
- Single Most Likely Diagnosis
- Cellulitis: This is a common cause of unilateral leg swelling and mottling, especially in the postpartum period where the risk of infection may be increased due to potential breaks in the skin or invasive procedures. The negative DVT ultrasound does not rule out cellulitis, as these are distinct conditions.
- Other Likely Diagnoses
- Lymphedema: Postpartum women can experience changes in lymphatic drainage, potentially leading to lymphedema. Mottling could be seen in chronic stages due to skin changes.
- Superficial Phlebitis: Inflammation of superficial veins can cause swelling, redness, and mottling, and while less common, it's a plausible diagnosis, especially if there's a history of trauma or intravenous lines.
- Lipodermatosclerosis: A condition characterized by inflammation and scarring of subcutaneous fat, often associated with chronic venous insufficiency, which could present with mottling and swelling.
- Do Not Miss Diagnoses
- Phlegmasia Cerulea Dolens (Blue Phlebitis): A severe form of DVT that can cause significant swelling and mottling. Although the DVT ultrasound was negative, this condition can sometimes be missed on initial ultrasound, especially if it involves the iliac veins or if the ultrasound was technically limited.
- Arterial Occlusion: While less common, acute arterial occlusion can present with sudden onset of swelling, pain, and mottling. This is a medical emergency requiring prompt intervention.
- Compartment Syndrome: Increased pressure within a muscle compartment can lead to swelling, pain, and potentially mottling due to compromised blood flow. This is an emergency that requires immediate diagnosis and treatment.
- Rare Diagnoses
- Erythema Induratum (Bazin Disease): A rare condition characterized by recurring nodules and ulcers on the calves, associated with tuberculosis. It could present with swelling and mottling but is much less common.
- Livedoid Vasculopathy: A rare condition involving the small blood vessels of the skin, leading to mottling, ulcers, and sometimes swelling. It's an unlikely cause but should be considered in the differential diagnosis of unexplained lower leg symptoms.