Anusitis/Pruritus Ani (Itchy Bottom)

What is pruritus ani?

 

Pruritus ani is the medical term for a persistent (chronic) itchy feeling around the anus. The main symptom is an urge to scratch your anus, which is difficult to resist. The urge to scratch may occur at any time. However, it tends to be more common after you have been to the toilet to pass a bowel motion and at night (particularly just before falling asleep). The itch may be made worse by:

  • Heat.

  • Wool.

  • Moisture or wetness around the anus. This may be caused by sweating, or by incomplete drying of that area after washing. It may also be caused by leaking urine (incontinence).

  • Stools (faeces) being in contact with the skin around the anus. This can be due to leaking of stools out of the anus, or due to incomplete cleaning after opening your bowels.

  • Stress and anxiety.

What causes an itchy bottom?

 

An itchy bottom (pruritus ani) is a symptom, not a final diagnosis. Various conditions may cause an itchy bottom. When the cause is another condition which has been identified, this is known as secondary pruritus ani. However, in many cases the cause is not clear. This is called 'idiopathic pruritus ani' which means 'itchy anus of unknown cause'.

 

Known causes of an itchy bottom

 

There are lots of possible causes. See the separate leaflets linked to each condition below for more detail. These are just some of the possible causes:


There are a number of skin conditions which may affect the skin around the anus and cause itch. For example:

  • Eczema.

  • Psoriasis.

  • Lichen sclerosus.

  • Lichen planus.

  • Seborrhoeic dermatitis.
     

  • An allergic or irritant dermatitis. Dermatitis means inflammation of the skin. This may be caused by:
     

    • Excess sweat and moisture around the anus. Young children who may not wipe themselves properly, adults with sweaty jobs and adults with a lot of hair round their anus may be especially prone to this.

    • Excess cleaning of the anal area.

    • Some soaps, perfumes, creams, or ointments, or the dye in some toilet tissue, may irritate (sensitise) the skin around the anus in some people. You may be 'allergic' to one or more of the ingredients in these products.

Other Causes include foods like citrus fruits, grapes, tomatoes, spices and peppers, large amounts of beer, milk and caffeine. Medicines may also lead to an itchy bottom, for example steroid medications which can weaken the immune system and cause increased risk of developing skin infections. Other examples include medications that result in diarrhea, which can irritate the anal skin and cause anusitis. 

Pruritus ani treatment

 

A particular treatment may be advised by a doctor or pharmacist. For example:

Speak to your doctor about other possible treatments if symptoms persist, as you may be referred to a specialist like a dermatologist or colorectal surgeon to make sure potential causes have not been missed.