Splendore-Hoeppli phenomenon in Pityrosporum folliculitis (pseudoactinomycosis of the skin).

Actinomyces-like granules showing the Splendore-Hoeppli phenomenon have been demonstrated in histologic material, e.g. uterine curettings, in various conditions unrelated to genuine actinomycotic infection. The exact nature of the granules and the mechanism of their formation is open to speculation. We report two patients with a follicular skin eruption (Pityrosporum folliculitis) where pseudoactinomycotic granules were found in the skin biopsies. To the best of our knowledge, such findings have not previously been reported, but supposedly they are not rare. In order to avoid an incorrect diagnosis of actinomycosis, and unnecessary therapy, it is important to be familiar with the phenomenon.