Macular Rash Differential Diagnosis
The following is a differential diagnosis for a macular rash, categorized for clarity and emphasis on critical considerations.
Single Most Likely Diagnosis
- Viral exanthem (e.g., measles, rubella, roseola): This is often the most common cause of a macular rash in both children and adults, characterized by a widespread, flat, and sometimes itchy rash.
Other Likely Diagnoses
- Allergic reactions (e.g., to medications, foods): These can cause a variety of rashes, including macular types, and are relatively common.
- Eczema (atopic dermatitis): While typically more localized and associated with itching, eczema can sometimes present with a macular rash, especially in its early stages.
- Contact dermatitis: A type of inflammation of the skin that occurs when the skin comes into contact with an irritant or allergen, leading to a macular rash among other symptoms.
Do Not Miss Diagnoses
- Meningococcemia: A severe infection caused by Neisseria meningitidis, which can present with a petechial or macular rash and is life-threatening if not promptly treated.
- Rocky Mountain spotted fever: A bacterial infection transmitted by ticks, characterized by a macular rash that can progress to a petechial rash, and is critical to diagnose early due to its high mortality rate if untreated.
- Secondary syphilis: Can cause a variety of rashes, including macular types, and is important to diagnose due to its implications for long-term health and transmission to others.
Rare Diagnoses
- Kawasaki disease: An acute febrile illness of childhood that can present with a macular rash, among other symptoms like fever, lymphadenopathy, and desquamation of the hands and feet.
- Erythema infectiosum (Fifth disease): Caused by parvovirus B19, it leads to a distinctive "slapped cheek" appearance and a macular rash on the body, more common in children.
- Drug-induced lupus: A rare condition triggered by certain medications, which can cause a macular rash as part of its symptomatology, along with other systemic symptoms.