To treat or not to treat? Management of guttate psoriasis and pityriasis rosea in patients with evidence of group A streptococcal infection

The association between guttate psoriasis and pityriasis rosea with Streptococcus pyogenes (S. pyogenes) is well established in the literature; however treatment guidelines and necessity have not been clarified with respect to the infectious etiology. Also, the exact role of Streptococcus in the immunopathogenesis of these entities, and the associated risk of development of scarlet fever and post-streptococcal sequelae, are not centrally reported. No single report or case series definitively establishes the coexistence between guttate psoriasis and post-streptococcal sequelae in the same patient, supporting the theories of autoimmune protection conferred between these entities. Laboratory investigations and treatment of Streptococcus in the setting of guttate psoriasis are not necessary, as anti-streptococcal treatment does not significantly modify the course of cutaneous disease, and there is no theoretical or documented risk of post-streptococcal sequelae. However, due to minimal data, antibiotics may still have a role in pityriasis rosea.