Illness
Psoriasis is sensitive to changes in the immune system. This means that conditions like illness that affect the immune system have the potential to trigger psoriasis. Some people experience more intense flares after or during a respiratory infection, an ear infection, or inflammation of the tonsils. In particular, streptococcal infections, such as strep throat caused by strep A bacteria, have been linked to psoriasis. Streptococcus infections often trigger the first incidence of guttate psoriasis in children, according to the National Psoriasis Foundation [4]. You should consider getting a test for strep if your psoriasis flares without any obvious cause. Not all strep throat infections show symptoms so it may be the underlying cause of your flare.