Various wet wipes containing perfume or other chemicals may irritate the baby’s skin.
Bad hygiene
Frequent defecation especially during periods of diarrhea facilitates the development of rashes. Similarly, frequent urination and the changing characteristics of urine during urinary tract infections increases the development of rashes.

Failure to change a diaper on a sufficiently regular basis also creates rashes. The baby diapers create a wet and warm environment for your baby’s skin. Another reason for skin rash is friction. Friction has even a higher impact on the skin in a wet and warm environment.

Microbial growth may occur on the irritated skin due to moisture and increasing heat. In this case, the irritated area becomes “infected”, generally leading the way to the development of fungal infections.

Ending of the breastfeeding period, transition from breast milk to formula or foods, changes with respect to baby’s nutrition also cause the development of rashes.
Teething periods, periods of treatment with antibiotics, eczema also create environments where the baby can develop rashes.
Some nutrients (such as tomatoes) passing from the breast milk may worsen the rash.