Differential Diagnosis
- Single most likely diagnosis
- Herpes Simplex Virus (HSV) infection: The patient's symptoms of severe itching, multiple blisters, and clear discharge are consistent with a herpes simplex virus infection, particularly given the location between the toes. The progression from pain to itching to blisters also fits this diagnosis.
- Other Likely diagnoses
- Bacterial infection (e.g., Staphylococcus aureus or Streptococcus pyogenes): Despite the lack of yellow discharge, a bacterial infection could still be present, especially if the patient's wound care has been effective in preventing the accumulation of pus. The localized redness and progression of symptoms could suggest a bacterial etiology.
- Insect bite reaction: The initial pain and subsequent itching could be indicative of an insect bite reaction, which can sometimes progress to blistering, especially in individuals with a strong allergic response.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Necrotizing fasciitis: Although the patient denies redness streaking up the foot and there's no mention of systemic symptoms like fever or severe pain out of proportion to the appearance of the wound, necrotizing fasciitis is a condition that must be considered due to its potential for rapid progression and high mortality rate.
- Gas gangrene: Similar to necrotizing fasciitis, gas gangrene is a rare but potentially deadly condition that could present with localized signs of infection and must be considered, especially if there's any suspicion of a deep or penetrating wound.
- Rare diagnoses
- Dyshidrotic eczema: This condition can cause blistering on the feet, particularly between the toes, but it's less likely given the acute onset and history suggestive of a bite or traumatic event.
- Contact dermatitis: An allergic reaction to something the patient has come into contact with could cause blistering and itching, but the history provided does not strongly support this diagnosis as the primary consideration.