Differential Diagnosis for Multiforme Erythema in a Baby
Single Most Likely Diagnosis
- Erythema Multiforme (EM): This is the most likely diagnosis due to the characteristic "target lesions" or "iris lesions" that are often seen in erythema multiforme. It is an immune-mediated condition that can be triggered by infections, medications, or other factors.
Other Likely Diagnoses
- Urticaria: Although urticaria (hives) typically presents with wheals, it can sometimes be confused with erythema multiforme, especially if the lesions are not classic target lesions. A detailed history and physical examination can help differentiate between the two.
- Viral Exanthem: Viral exanthems are common in infants and can present with a variety of rash types, including maculopapular, morbilliform, or even target-like lesions. The diagnosis is often based on the clinical presentation and associated symptoms like fever or upper respiratory symptoms.
- Allergic Contact Dermatitis: This condition occurs when the skin comes into contact with an allergen, leading to an immune response and rash. In babies, common allergens include metals (like nickel), fragrances, or certain chemicals in diapers or clothing.
Do Not Miss Diagnoses
- Stevens-Johnson Syndrome (SJS): A severe form of skin and mucous membrane disorder, usually a reaction to medication or infection. It can present similarly to erythema multiforme but is more severe and involves mucous membranes. Early recognition is crucial due to its high morbidity and mortality.
- Toxic Epidermal Necrolysis (TEN): Considered a more severe form of SJS, TEN involves widespread skin necrosis and detachment. It is usually drug-induced and has a high mortality rate if not promptly recognized and treated.
- Kawasaki Disease: An acute febrile illness of childhood that can present with rash, fever, conjunctivitis, and changes to the lips and oral cavity. It is important to consider due to its potential to cause coronary artery aneurysms if not treated.
Rare Diagnoses
- Neonatal Lupus Erythematosus: A rare condition caused by the transplacental passage of autoantibodies from a mother with lupus to her fetus. It can present with a variety of skin manifestations, including a rash similar to erythema multiforme.
- Acute Hemorrhagic Edema of Infancy: A rare form of vasculitis that presents with purpura, edema, and target-like lesions. It is considered a benign condition but can be alarming due to its appearance.