title: dtype argument ignored when index_col is specified in pandas read_excel
body: <p>I have a simple excel table that consists of two columns, and i want to read it in a python script using pandas read_excel:</p>
  <div class="s-table-container">
  <table class="s-table">
  <thead>
  <tr>
  <th>SKU_ID</th>
  <th>Some_Information</th>
  </tr>
  </thead>
  <tbody>
  <tr>
  <td>10001</td>
  <td>example1</td>
  </tr>
  <tr>
  <td>10002</td>
  <td>example2</td>
  </tr>
  </tbody>
  </table>
  </div>
  <p>The SKU_ID column should be the index and also its dtype should be <em>str</em> (because some SKU_IDs have letters). I was trying to read it with the following code:</p>
  <p><code>df = pd.read_excel('file.xlsx', dtype={'SKU_ID': str}, index_col='SKU_ID'}</code></p>
  <p>But the result of that is a Dataframe in which the index (SKU_ID) is <em>int64</em>.</p>
  <p>To work around this issue I have done the following:</p>
  <pre><code>df = pd.read_excel('file.xlsx', dtype={'SKU_ID': str} 
  df.set_index('SKU_ID', inplace=True)
  </code></pre>
  <p>which basically does the same thing, but keeps the index as type <em>str</em>.</p>
  <p>Is there a way to set SKU_ID as the index and ALSO as <em>str</em> when reading the excel file?</p>