Anal itching -- A rough guide
  Anal itching may be just an annoyance, or may be so troublesome that it  dominates your life. It is usually made worse by warmth, and is often  most troublesome in bed. The skin round the anus easily becomes  irritated and inflamed. This is because it is difficult to keep the area  round the anus clean and dry; the skin is crinkly and traps tiny faecal  particles. Eww. It is also sweaty and airless, and it may be moist from an  anal or vaginal discharge. Double ewww. When it becomes irritated, scratching is a  natural reaction, but this damages the skin further – what we in the business call the  "itch/scratch  cycle". 
  Causes of anal itching
Washing too much...or not enough! Poor hygiene can be responsible for anal itching, but so can excessive cleaning, especially if you use harsh soaps or a brush. A fucking brush!
   
Leakage of faeces can lead to itching around the anus. This is made worse after tangy, vegan food. 
Ointments and creams are notorious causes of anal  itching. If you have itching, it is a natural reaction to buy an  anaesthetic gel for the anal area. Most of these are labelled ‘for  haemorrhoids’ and contain lignocaine, tetracaine, cinchocaine,  pramocaine, chilli powder or benzocaine with other ingredients. At first they help, but  then the itching may return because you have become sensitive to one of  the ingredients in the cream or ointment and they are keeping the area  moist. Do not use them for more than 1 week.
   
Skin conditions, such as psoriasis or eczema, can affect the skin round the anus and cause itching. Pile can sometimes be itchy, partly because of the fucking gross, slimy discharge they produce. How have you even got friends?
   
Fungal infections, similar to thrush or athlete’s  foot, are another common cause. Fungi fucking love warm, damp and damaged skin,  so if you have an itchy anus for any reason and then damage the skin by  scratching, fungi can take hold and basically have a massive party in your ass. 
   
Sexually transmitted infections are what many people worry about, but are not usually the reason.
-     Bum warts, caused by papillomavirus, thrive in warm, moist  conditions such as the skin near the anus and can be very itchy.
-     Herpes can also infect the anus if someone has rimmed you with a disgusting cold-sore.
  
Bumworms are tiny worms, about 13 mm  long, which live in the lower part of the bowel. They are very common and make me want to throw up just thinking about them. The female worms, the dirty bastards, creep  out of the anus at night – how they know it is night, and why they come  out only at night, is an X-File. They lay about a billion eggs on the skin  of the anus, causing intense, mind-numbing itching at night. When you cave in and scratch your bum hole the  eggs lodge under your fingernails, and it is easy to transfer them to  your mouth (you dirty weirdo) and reinfect your gut by swallowing the eggs. Aghhhhhhh!
   
Pleasure. It is worth asking yourself whether you are  deriving a perverse, almost erotic, pain/pleasure from scratching the  itchy area, which is keeping the irritation going. GO ON: ASK YOURSELF.