For an itchy fungal skin rash, you can use over-the-counter antifungal creams containing Clotrimazole, Miconazole, or Terbinafine. Apply a thin layer to the clean, dry affected area twice daily, extending slightly beyond the rash border, for 1 to 2 weeks, even if symptoms clear up early. Keep the area dry, wear loose cotton clothing, and avoid scratching. If the rash does not improve after two weeks, spreads, or becomes increasingly painful and red, please consult a doctor, as you may require a prescription-strength topical or oral antifungal medication.