Differential Diagnosis for Cough, Arthalgia, Fever, and Skin Rash
Single Most Likely Diagnosis
- Viral Exanthem: This is a common condition that presents with a combination of fever, cough, arthalgia, and skin rash, often seen in viral infections such as influenza, respiratory syncytial virus (RSV), or adenovirus. The symptoms are non-specific and can be seen in a variety of viral infections, making it a likely diagnosis.
Other Likely Diagnoses
- Influenza: Influenza can present with cough, fever, and body aches, including arthalgia. A skin rash can also occur, although it is less common.
- Mononucleosis: Caused by Epstein-Barr virus (EBV), mononucleosis can present with fever, cough, arthalgia, and a skin rash, particularly if the patient is taking ampicillin.
- Lyme Disease: Early stages of Lyme disease can present with fever, arthalgia, and a characteristic skin rash (erythema migrans), although cough is not a typical symptom.
Do Not Miss Diagnoses
- Meningococcemia: This is a life-threatening condition caused by Neisseria meningitidis, which can present with fever, cough, arthalgia, and a skin rash (petechiae or purpura). It requires prompt diagnosis and treatment.
- Rocky Mountain Spotted Fever (RMSF): RMSF is a tick-borne illness that can present with fever, headache, and a skin rash, as well as cough and arthalgia in some cases. It is a serious condition that requires prompt treatment.
- Endocarditis: Infective endocarditis can present with non-specific symptoms, including fever, arthalgia, and a skin rash (e.g., Janeway lesions), as well as cough if there is embolic phenomena affecting the lungs.
Rare Diagnoses
- Adult-Onset Still's Disease: This is a rare autoimmune condition that can present with fever, arthalgia, and a skin rash, as well as cough in some cases.
- Sarcoidosis: Sarcoidosis is a rare condition that can affect multiple organs, including the lungs, joints, and skin, presenting with cough, arthalgia, fever, and a skin rash in some cases.
- Ehrlichiosis: This is a tick-borne illness that can present with fever, headache, and a skin rash, as well as cough and arthalgia in some cases. It is a rare condition that requires prompt diagnosis and treatment.