Controversy exists about triggers of recurrent outbreaks of genital herpes, typically due to HSV-2. No scientific studies have clearly documented such triggers, and the objective data available suggest that outbreaks are not influenced by stressful events, anxiety, depression, or similar influences. The clinical experience of most experts involved in clinical care is that attempts by infected persons to modify external triggers are virtually never effective in controlling symptomatic outbreaks of genital herpes. Similarly, neither objective data nor biological plausibility support the notion that excessive usage of antibiotics affects the immune system's ability to keep the disease within the nerve ganglia (particularly as antibiotics are useless against viruses of any type) or otherwise affect herpes recurrences, nor the occasional assertion that "chronic" genital herpes is in any way related to low-level food allergy. Symptoms usually appear within 2 weeks. The sores usually heal within 2 - 4 weeks. This varies greatly on the individual however, as some may not exhibit any symptoms for years, and some may not show symptoms at all