Differential Diagnosis for Maculopapular Rash
Single Most Likely Diagnosis
- Tinea corporis: A common fungal infection that can cause a maculopapular rash, often appearing after a decade or more of exposure to the fungus. The rash typically starts as small, circular patches that can grow and merge, forming larger lesions.
Other Likely Diagnoses
- Atopic dermatitis (eczema): A chronic skin condition characterized by itchy, inflamed skin, which can manifest as a maculopapular rash. It often starts in childhood but can persist or recur in adulthood.
- Contact dermatitis: An allergic or irritant reaction to substances like soaps, detergents, or metals, leading to a maculopapular rash. This condition can occur at any age, depending on exposure.
- Psoriasis: An autoimmune condition causing red, scaly patches on the skin, which can sometimes appear as a maculopapular rash. It can start at any age, including after a decade or more of being symptom-free.
Do Not Miss Diagnoses
- Secondary syphilis: A sexually transmitted infection that can cause a maculopapular rash, among other symptoms. It's crucial to consider this diagnosis due to its potential for serious complications if left untreated.
- Lyme disease: A bacterial infection transmitted by tick bites, which can cause a distinctive "bull's-eye" rash (erythema migrans) but sometimes presents as a maculopapular rash. Missing this diagnosis can lead to severe neurological and cardiac complications.
- Drug reactions: Certain medications can cause a maculopapular rash as an adverse reaction. Identifying and discontinuing the offending drug is critical to prevent further complications.
Rare Diagnoses
- Pityriasis rosea: A rare skin condition characterized by a maculopapular rash, often preceded by a "herald patch." Its cause is unknown, but it typically resolves on its own.
- Kawasaki disease: A rare condition that mainly affects children but can occur in adults, causing a maculopapular rash, fever, and other symptoms. It's essential to recognize this condition due to its potential for cardiac complications.
- Viral exanthems: Certain viral infections, like measles or rubella, can cause a maculopapular rash. While vaccination has made these conditions rare in many areas, they should still be considered, especially in unvaccinated individuals or during outbreaks.