Is balanitis an STI?
Usually not. The two commonest causes are thrush and soap irritation, neither of which is sexually transmitted.
Some sexually transmitted infections can present this way, though — so if there is a relevant history, an ulcer, or a partner with symptoms, screening is sensible rather than alarmist.
Can I pass it to my partner?
Candidal balanitis can pass between partners, and where a partner has recurrent thrush, treating both is sometimes reasonable. Irritant balanitis is not transmissible at all.
Does it mean I have diabetes?
Not from a single episode. From recurrent episodes, it is a genuine possibility worth excluding.
Raised blood sugar means sugar in the urine, which feeds yeast under the foreskin. Recurrent balanitis is a recognised first presentation of type 2 diabetes, and an HbA1c is a reasonable and quick check.
Should I wash it more?
Almost certainly not with soap. Over-washing with soap and shower gel is itself one of the commonest causes. Retract gently, rinse with warm water only, and dry properly.
How long does it take to clear?
Candidal balanitis usually settles within a week of starting an antifungal. Irritant balanitis improves within days of stopping soap. If there is no improvement in two weeks, the diagnosis needs revisiting — lichen sclerosus in particular is often missed for years.
Will I need to be circumcised?
Very rarely, and not as a first response. It is considered for genuinely recurrent severe balanitis, for lichen sclerosus that has not responded, or for a tight foreskin causing repeated problems — and that is a urology decision, not one to make from an online consultation.