Guttate psoriasis is often triggered by a streptococcal infection, typically streptococcal pharyngitis. Acute glomerulonephritis, inflammation of the renal glomerulus, can follow streptococcal pharyngitis or skin infection. The most common of these infections include streptococcal pharyngitis (strep throat) and impetigo. It is commonly used to treat acute otitis media, pharyngitis, sinusitis, and gonorrhea. Effects of infection include granulomatous lymphadenopathy, pneumonitis, pharyngitis, skin infections, and endocarditis. Examples of mild "S. pyogenes" infections include pharyngitis (strep throat) and localized skin infection (impetigo). Secondary bacterial infections may occur resulting in sinusitis, pharyngitis, or an ear infection. Untreated streptococcal pharyngitis usually resolves within a few days. Other causes include other infections (such as streptococcal pharyngitis), trauma, and tumors. Streptococcal pharyngitis or strep throat is caused by a group A beta-hemolytic streptococcus (GAS). "S. pyogenes" causes diseases ranging from pharyngitis to life-threatening impetigo including necrotizing fasciitis. Spreading of infection through blood has been suggested for those with streptococcal pharyngitis. Poor oral hygiene, pharyngitis, and mucosal ulceration are also predisposing factors for infection. Chronic pharyngitis may be catarrhal, hypertrophic, or atrophic. Pain in sore throat is the hallmark of acute pharyngitis.