For his runny nose, saline nasal drops can safely clear congestion. The thigh itching suggests chafing or a fungal infection; applying a zinc oxide barrier cream or a mild OTC antifungal cream (like clotrimazole), while keeping the area clean and dry, should help. His poor appetite for solids is likely linked to nasal congestion; offer small, frequent meals and focus on hydration. Please consult a pediatrician before administering any oral medications, such as antihistamines or deworming syrups, to ensure correct diagnosis and safe dosages for his age.