Healthy patients with early painful herpes zoster were treated with corticosteroid orally or lactose tablets in a double-blind fashion. The duration of postherpetic neuralgia was shortened by treatment with the corticosteroid. Corticosteroid therapy did not affect pain during the first two weeks or the rate of skin healing. The duration of postherpetic neuralgia could not be predicted by the healing rate of the skin. Control patients less than 60 years old had rapid resolution of their neuralgia while those more than 60 years old had slower resolution of the pain. Corticosteroid therapy did not cause generalization of the eruption.
Eaglstein WH, Katz R, Brown JA. The Effects of Early Corticosteroid Therapy on the Skin Eruption and Pain of Herpes Zoster. JAMA. 1970;211(10):1681–1683. doi:10.1001/jama.1970.03170100043009