Background: Psoriasis is characterized by immune activation and increased epidermal proliferation. Cyclosporine acts by reducing T lymphocyte numbers and lymphokine production. Anthralin inhibits keratinocyte proliferation.
Objective: We investigated whether topical anthralin would augment clearing of psoriasis produced by systemic cyclosporine.
Methods: Twelve patients with psoriasis were treated with cyclosporine (5 mg/kg per day). Patients applied anthralin only to plaques on half of their body. They were treated until a remission or maximum benefit was achieved. Disease activity was assessed by a severity index and quantitative histopathologic markers.
Results: Of the 12 patients, the skin of five cleared within 10 weeks irrespective of anthralin use. The other seven (slow responders) continued treatment for a mean of 18 weeks. Slow responders had a significantly lower severity index, a thinner epidermis, fewer CD8+ cells, and fewer proliferating keratinocytes on the anthralin-treated side than on the non-anthralin-treated side.
Conclusion: The combination of cyclosporine and topical anthralin is effective in patients who are slow to respond to cyclosporine alone.