Differential Diagnosis of Blisters on Hand and Elbow and Sore Throat

Single Most Likely Diagnosis

• Hand, Foot, and Mouth Disease (HFMD): This is a common viral illness that typically affects children but can also occur in adults. It is characterized by sores in the mouth and a rash on the hands and feet, which can sometimes extend to the elbows. The sore throat is a common accompanying symptom.

Other Likely Diagnoses

• Impetigo: A highly contagious bacterial skin infection that can cause blisters or sores on the skin, often accompanied by a sore throat if the infection is caused by streptococcal bacteria.
• Eczema (Dyshidrotic): A type of eczema that causes small, itchy blisters on the hands and feet, sometimes accompanied by a sore throat if there is an associated infection or allergic reaction.
• Allergic Contact Dermatitis: An allergic reaction to something that has come into contact with the skin, causing blisters and a rash, potentially accompanied by a sore throat if the allergen affects the throat or if there is a secondary infection.

Do Not Miss Diagnoses

• Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN): These are severe skin and mucous membrane disorders, usually a reaction to medication or infection. They can cause blisters, skin peeling, and sores in the mouth and throat, and are medical emergencies.
• Pemphigus Vulgaris: A chronic autoimmune skin disease that causes blisters on the skin and mucous membranes, which can lead to severe complications if not treated promptly.
• Infectious Mononucleosis (Mono): Caused by the Epstein-Barr virus, it can lead to a sore throat and sometimes a rash, which might include blisters, especially if the patient is taking certain medications like ampicillin.

Rare Diagnoses

• Bullous Pemphigoid: An autoimmune disease that causes large blisters on the skin, which can occasionally be accompanied by a sore throat if there is an associated infection.
• Dermatitis Herpetiformis: A skin condition characterized by intensely itchy blisters, often associated with celiac disease, and could potentially be accompanied by a sore throat due to malabsorption or associated conditions.
• Epidermolysis Bullosa Acquisita (EBA): A rare autoimmune disease that causes the formation of blisters on the skin, which might be accompanied by a sore throat in the context of an overall systemic illness or secondary infection.