XML unencoding in Scala

I've coded a function for XML unencoding in Scala. This function should replace encoded sequences as &, <, etc. with &, <, etc.

def unencode(encoding: Seq[(Char, String)])(inp: String): String =
  if (inp == "") inp else {
    val (c, s) =
      encoding.find {case (k, v) => inp.startsWith(v)}
        .map {case (k, v) => (k, inp.drop(v.size))}
        .getOrElse (inp.head, inp.tail)
    c + unencode(encoding)(s)
  }

(It's just an exercise. I would probably use commons_lang)

Does it make sense ? How would you fix/improve it ?