Differential Diagnosis for Red Spots on Lower Legs after Standing for Long Periods

Single Most Likely Diagnosis

• Stasis Dermatitis: This condition is characterized by red, itchy, and swollen skin on the lower legs due to prolonged standing, which leads to poor circulation and fluid accumulation. The symptoms match the presentation of red spots on the lower legs after standing for long periods.

Other Likely Diagnoses

• Varicose Eczema: Similar to stasis dermatitis, varicose eczema is associated with poor circulation and can cause red, itchy patches on the skin, particularly on the lower legs.
• Contact Dermatitis: This is a skin reaction that occurs after contact with an irritant or allergen, which could be more pronounced or noticeable after standing for long periods due to increased pressure and friction on the skin.
• Folliculitis: An inflammation of the hair follicles, which can appear as red spots and can be exacerbated by friction and pressure from standing.

Do Not Miss Diagnoses

• Deep Vein Thrombosis (DVT): Although DVT typically presents with swelling, pain, and warmth of the affected leg, it's crucial not to miss this diagnosis due to its potential for severe complications, such as pulmonary embolism.
• Cellulitis: A bacterial skin infection that can cause redness, swelling, and warmth, usually on one leg. It requires prompt antibiotic treatment to prevent serious complications.
• Vasculitis: Inflammation of the blood vessels, which can cause a variety of skin symptoms including red spots, and can be associated with systemic diseases that may have serious consequences if not addressed.

Rare Diagnoses

• Erythema Nodosum: A condition characterized by the sudden formation of painful, red lumps on the skin, often on the lower legs. It can be associated with various underlying conditions, including infections and autoimmune diseases.
• Cutaneous Polyarteritis Nodosa: A rare disease characterized by inflammation of the blood vessels in the skin, which can cause red spots, nodules, and ulcers, particularly on the lower legs.
• Livedo Reticularis: A mottled, purplish discoloration of the skin, which can sometimes appear as red spots, due to impaired circulation. It can be associated with various underlying conditions, including vasculitis and cardiovascular diseases.