What Causes Eczema in Infants?

Infantile eczema—most commonly presenting as atopic dermatitis—is a prevalent inflammatory skin condition affecting up to 20% of children worldwide. Its onset typically occurs within the first six months of life, with characteristic features including dry, scaly, erythematous plaques that frequently involve the cheeks, scalp, and extensor surfaces of the limbs.

The pathogenesis is multifactorial, rooted in a complex interplay between genetic predisposition, epidermal barrier dysfunction, and immune dysregulation. A significant proportion of affected infants carry loss-of-function mutations in the *FLG* gene, which encodes filaggrin—a key structural protein essential for stratum corneum integrity. This defect compromises the skin’s physical barrier, facilitating transepidermal water loss and increasing permeability to environmental allergens and irritants.

Environmental contributors include exposure to harsh soaps, synthetic fabrics, temperature fluctuations, low humidity, and airborne allergens such as house dust mites or pet dander. While food sensitization—particularly to cow’s milk protein, hen’s egg, or peanuts—is often suspected by caregivers, true IgE-mediated food allergy is confirmed in only a minority of cases and should not be assumed without clinical evaluation and appropriate testing.

Importantly, infantile eczema is not caused by poor hygiene, vaccination, or maternal diet during breastfeeding—common misconceptions unsupported by current evidence. Instead, management focuses on consistent emollient use, gentle skin care practices, and, when indicated, short-term topical corticosteroids or calcineurin inhibitors under medical supervision.