Many investigators have reported proliferation of terminal cutaneous nerves and upregulation of various neuropeptides (substance P, vasoactive intestinal polypeptide, calcitonin gene-related peptide) in psoriatic lesions (Raychaudhuri et al., 1998). Nerve growth factor promotes growth of nerves and causes upregulation of neuropeptides like substance P and calcitonin gene-related peptide. In addition, nerve growth factor is mitogenic to keratinocytes, activates T-lymphocytes and can induce migration of inflammatory cellular infiltrates, histological features characteristic of psoriasis (Raychaudhuri et al., 1998).