Folliculitis decalvans (FD) is a chronic inflammatory disease with an unknown etiology. FD is characterized by chronic suppurative folliculitis, is often accompanied by pruritus or even pain, and ultimately progresses to cicatricial alopecia. Adult men have a tendency to develop this disease. The current treatments mainly consist of antibiotics, vitamin A derivatives, immune therapies, and biologics. However, some cases are intractable. Here, we present a case of recalcitrant FD that was successfully treated by photodynamic therapy with topical aminolevulinic acid.