Differential Diagnosis for Itchy Bite on the Arm
- Single Most Likely Diagnosis
- Insect bite (e.g., mosquito, flea, or bed bug): This is the most common cause of itchy bites and is often seen in individuals who have been outdoors or in areas where insects are prevalent.
- Other Likely Diagnoses
- Allergic contact dermatitis: This condition occurs when the skin comes into contact with an allergen, leading to an itchy and inflamed reaction.
- Scabies: A parasitic infection caused by the mite Sarcoptes scabiei, which can cause intense itching and is highly contagious.
- Flea bite allergy: Some people may develop an allergic reaction to flea bites, leading to intense itching and inflammation.
- Do Not Miss Diagnoses
- Lyme disease: Although less common, Lyme disease is a serious condition caused by the bite of an infected tick, and early diagnosis is crucial for effective treatment.
- Rocky Mountain spotted fever: Another tick-borne illness that can be life-threatening if not treated promptly.
- Ehrlichiosis: A bacterial infection transmitted by ticks, which can cause severe symptoms if left untreated.
- Rare Diagnoses
- Leishmaniasis: A parasitic disease spread by the bite of an infected sand fly, which can cause skin lesions and other systemic symptoms.
- Tungiasis: An infection caused by the burrowing flea Tunga penetrans, which can lead to intense itching and skin lesions.
- Myiasis: A rare condition where fly larvae infest the skin, often causing itching and inflammation.