Croup is a viral illness that afflicts the upper airway, causing swelling in the air tube, which leads to a dry, barking-type cough and often a hoarse voice. The cough usually worsens at nighttime. Humidified air, warm or cool, may be beneficial. Try steaming up a shower, like a sauna, and sit in there with the child for 20 minutes. On a cool winter night, drive with the child (in a carseat) around the block with the window cracked halfway to allow air in the child's face. Avoid antihistamines (Zyrtec, Claritin, Benadryl, Dimetap). If your child's respiratory distress increases, seek immediate help at the nearest Emergency Room.