It is narrated from Hazrat Abu Umamah (may Allah be pleased with him) that the Noble Prophet (peace and blessings be upon him) said: The complete visiting of a sick person is that you place your hand on his forehead or hand and ask how he is. And the completion of the etiquette of your mutual meeting is through "handshaking."
Hadith Referenceمسند احمد / مسند الأنصار رضي الله عنهم / 22236
Hadith Gradingحکم دارالسلام:إسناده ضعيف جدا ، عبيدالله بن زحر وعلي بن يزيد ضعيفان