Differential Diagnosis for 8 Blisters on the Top of Right Foot with Slight Redness

• Single most likely diagnosis
  • Contact dermatitis: This is the most likely diagnosis due to the presence of blisters and slight redness, which are common symptoms of an allergic reaction or irritation from an external source such as shoes, socks, or chemicals.
• Other Likely diagnoses
  • Dyshidrotic eczema: Characterized by small, itchy blisters on the hands or feet, this condition could be a possible diagnosis if the blisters are extremely itchy and the patient has a history of eczema.
  • Friction blisters: Given the location on the top of the foot, friction from poorly fitting shoes could be a cause, especially if the patient has recently increased their physical activity or worn new shoes.
  • Herpes simplex infection: Although less common on the foot, herpes simplex can cause blister-like lesions and should be considered, especially if the patient has a history of herpes infections.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Cellulitis: An infection of the skin and subcutaneous tissues that can start as redness and swelling and could be life-threatening if not treated promptly, especially in patients with compromised immune systems.
  • Necrotizing fasciitis: A severe infection that destroys tissue under the skin, including fat and the tissue covering the muscles (fascia), which is a medical emergency.
• Rare diagnoses
  • Pemphigus: A group of rare skin disorders that cause blistering of the skin and mucous membranes, which could be considered if other diagnoses are ruled out and the patient has systemic symptoms.
  • Epidermolysis bullosa: A rare genetic condition that results in fragile skin and blisters, which would be an unlikely diagnosis in an adult presenting for the first time but should be considered in children or if there's a family history.