For 20 months the area around my anus and between my anus and scrotum hurts whenever I sit (and often even just standing). The pain is a burning/prickly/stinging/pinching (no itching, though) of the skin.
The area itself doesn't look remarkable. There is usually a redness around my anus which darkens and extends when the area becomes more irritated (redness is ~1 cm radius normally). There is a tab of skin next to my anus (towards my scrotum) that has been called a "collapsed hemorrhoid" or a "skin tag" by different doctors. Also, there is a small crevice (1 cm long, 3 or 4 mm deep) alongside this tab that, when pulled apart, is pink inside. This crevice goes to the edge of my anus but not inside (ie not an anal fissure). None of these features are particularly sensitive when they are touched or pressed on, but if the area is probed/manipulated then afterwards it becomes significantly more sore for a day or two. Also, there is a wetness that correlates with degree of irritation. It is a slippery, brown stuff (probably mucus; one doctor told me that the anus is just one huge mucus membrane). I think the irritation is causing the mucus, and not the other way around, because cleaning it off does not improve my condition. The skin itself is smooth (no bumps, pustules, etc.).
I have been to several types of doctors without resolution. My family doc first thought it was hemorrhoids, but it wasn't. Because the area involved my anus, I was sent to a colorectal surgeon who found an anal fissure. Surgery corrected the fissure with no change in symptoms. A nerve specialist did an MRI to confirm that the problem wasn't with the nerves. He also put me on amitryptyline (20mg daily) and gabitril (2 mg 3x a day), thinking that the problem was due to a nerve feedback loop, but that didn't help. I have been many times to a dermatologist, who gave me (one at a time): A&D, Aquaphor, gentamicin sulfate, Aclovate, fluocinonide 0.05%, dutivate 0.005%, Luxic 0.12%, LidaMantle HC, Neosporin, Lotrimin Ultra, zonalon 5%. He also found yeast and treated with fluconazol and lamisit. Later cultures confirmed the yeast was gone, with no change in symptoms. Basically the dermatologist threw all the "weapons" he had at the problem without really understanding the root cause, and now he's out of ammo.
There are ways to worsen the condition. Sitting makes it worse, as does friction (scrubbing is deadly) and some of the creams: Lamisit really irritates the area. When I used it, I covered a greater area than what was bothering me. In the area that wasn't bothering me, Lamisit didn't cause any irritation. In the area that was bothering me, it really made it worse. In all these cases of making things worse, the feeling is just intensified (rather than a new type of irritation appearing).
Finally: this condition literally came about overnight. Two years ago, the same thing happened. Then it resolved by itself after about a week. I can rule out STD and physical trauma.