Home Contact Sitemap Checkout

Suite 303, 2377 – 111 Street NW Edmonton, Alberta Canada, T6J 5E5



Home/Resources /Patient Conditions/Cysts - Epidermoid and Sebaceous Print This Page

Cysts - Epidermoid and Sebaceous 

By definition, cysts are closed sacs that have two main features:

    • A lining. 
    • Contents that are liquid or semi-solid.
       

The lining

Differences between the lining of epidermoid and pilar cysts can be seen under the microscope:

    • The lining of an epidermoid cyst looks like the epidermis (the outermost layer of cells in the skin). 
    • The lining of a pilar cyst is made up of cells like those found in the roots of hairs
       


The contents

Both types of cyst contain a cheesy material, looking rather like toothpaste.  This is made of soggy keratin - the material that makes up hair and the outer layer of the skin.



Causes


Epidermoid cysts affect young and middle aged adults.  They can come up after a hair follicle has been inflamed, so they are common in acne. 


Pilar cysts affect women more often than men, and tend to come up in middle age.  They run strongly in families (see below). 


Epidermoid cysts by themselves are usually not hereditary, but they may be part of several rare conditions that are.  Pilar cysts run strongly in some families, being inherited as an autosomal dominant trait – which means that there is a 1 in 2 chance that each child of an affected parent will inherit the condition.




Symptoms


Both types grow slowly.  Some become infected (red and sore) from time to time.  They may then discharge cheesy foul-smelling pus.  Those on the scalp can catch on the comb: others may look embarrassing.



The cysts look like

They are round, sometimes dome-shaped bumps, lying just under the skin surface.  Some are yellow or whitish. A small dark plug is often present, through which it may be possible to squeeze out some of the cyst’s contents.  The cysts range in size from those that are smaller than a pea to those that are several centimeters across. They can occur anywhere on the skin but:


Pilar cysts are most common on the scalp, where several can often be found. 

    • Epidermoid cysts are most common on the face, neck and upper trunk.   




Cysts are diagnosed by 

  • Your doctor will make the diagnosis on the appearance of the bump.  If there is any doubt, the cyst can be removed and checked under the microscope.
  • Cysts can be cured by several simple and effective ways for removing them under local anesthetic.




Treatments


Treating cysts

  • Epidermoid and pilar cysts are harmless, and small ones that give no trouble can safely be left alone.  
  • Your doctor may give you an antibiotic if your cyst becomes infected.  
  • Cysts can be injected with a type of cortisone solution.  Cysts will shrink 4 out of 5 times.   
  • Both types of cyst are easy to remove under a local anaesthetic but this does leave a scar.



Reasons for removal include

  • If the cyst is embarrassing and easily seen by others. 
  • If it interferes with everyday life, for example by catching on your comb. 
  • If the cyst becomes infected. 
  • It is important that the doctor removes the whole of the lining during the operation as doing so cuts down the chance of the cyst growing back.



What you can do

If you find any sort of lump in your skin, you should consult your doctor.  Epidermoid and pilar cysts are not dangerous, but your doctor should be asked to look at them to make sure that the diagnosis is right.