Alopecia areata (AA) is regarded as a tissue-specific autoimmune disease for which several therapies have been suggested to modify the immune reaction against HFs, such as contact immunotherapy, psoralen plus ultraviolet A (PUVA), corticosteroids, cyclosporine, minoxidil, and dithranol. However, severe type AA, such as alopecia totalis (AT) and alopecia universalis (AU), often show resistance against these therapies. We applied a combination therapy with oral corticosteroid and oral PUVA for intractable cases of AT and AU. These patients took 20 mg/day corticosteroid and were irradiated with UVA on the whole body 2 h after taking methoxsalen for 1 month. In all patients, the terminal hair on the whole scalp regrew after 2 months. Two patients had a relapse of hair loss 3 months after the termination of the treatment. FACS analysis revealed that the CD4+CD25(high) and CD4+CD25+FOXP3+ Treg population in PBMC was increased after the combination therapy. Furthermore, the number of infiltrating cells decreased and FOXP3+ cells were often found in lesion skin after the combination therapy. Mitogen-induced proliferation tests showed low responses against PHA and Con A after the combination therapy. Taken together, the combination therapy may modify the systemic immune system and increase the number of Treg cells, resulting in improvement of recalcitrant AA.