What are the other Names for this Condition? (Also known as/Synonyms)

• Isthmus-Catagen Cyst
• Pilar Cyst

What is Trichilemmal Cyst? (Definition/Background Information)

• Trichilemmal Cyst (also called Pilar Cyst) is the second most common cyst of skin that is generally observed in adults. It occurs on the skin as a painless nodule
• This benign cyst is usually solitary and can be present anywhere in the body; however, the most common location is the scalp
• The cause and risk factors for Trichilemmal Cyst are unknown, but if multiple cysts are present on the body, then a familial inheritance may be observed
• In a majority of cases, no treatment in necessary, unless it causes discomfort in the individual including cosmetic issues
• A simple surgical excision of the tumor is considered curative. The prognosis for Trichilemmal Cyst is excellent with suitable treatment

Who gets Trichilemmal Cyst? (Age and Sex Distribution)

• Trichilemmal Cyst is a very common benign cyst that can occur at any age, but is more common in adults
• It is thought that up to 10% of the human population may have Trichilemmal Cysts
• Both males and females may be affected
• Individuals of all racial and ethnic background may be affected. Worldwide, no geographical localization of the cyst has been reported

What are the Risk Factors for Trichilemmal Cyst? (Predisposing Factors)

• Currently, no risk factors have been identified for Trichilemmal Cyst
• Nevertheless, a positive family history may influence the development of multiple cysts on the body

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Trichilemmal Cyst? (Etiology)

• The cause of development of Trichilemmal Cyst is unknown. Research is currently being undertaken to identify the relevant causal factors
• If numerous cysts appear all over the body, then it may be due to a family history of the condition

What are the Signs and Symptoms of Trichilemmal Cyst?

Most Trichilemmal Cysts are asymptomatic. In some, the signs and symptoms observed include:

• It usually occurs as a single cyst on the skin. It can range in size from 5 mm to 5 cm
• The skin over the nodules may have a reddish discoloration
• These cysts are usually painless and non-itchy. They are mostly well-demarcated and firm to touch
• Though Trichilemmal Cyst can occur at any location in the body, over 90% of these cysts are seen on the scalp

Trichilemmal Cyst typically occurs as a single cyst that grows slowly. However, multiple cysts may also be seen, when a family history of the condition is present.

How is Trichilemmal Cyst Diagnosed?

A diagnosis of Trichilemmal Cyst may involve the following:

• A thorough medical history and physical examination
• Dermoscopy: It is a diagnostic tool where a dermatologist examines the skin using a special magnified lens
• Wood’s lamp examination: In this procedure, the healthcare provider examines the skin using ultraviolet light. It is performed to examine the change in skin pigmentation
• Skin biopsy: A skin biopsy is performed and sent to a laboratory for a pathological examination. The pathologist examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis

Note: A biopsy may be performed to rule out other skin conditions with similar signs and symptoms.

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Trichilemmal Cyst?

In most cases, Trichilemmal Cysts are benign cysts that do not cause any significant complications. However, the following factors may be a cause for concern:

• Sometimes, the cysts can proliferate and multiply resulting in a condition called Proliferating Trichilemmal Cyst. These cysts have the potential to infiltrate into the local tissues and destroy surrounding structures
• The presence of multiple cysts may also result in cosmetic issues
• Sometimes, they can rupture, become infected and release pus. This condition is called a Ruptured Pilar Cyst or Ruptured Trichilemmal Cyst. When these heal, they can leave a scar behind

How is Trichilemmal Cyst Treated?

The treatment of Trichilemmal Cyst may involve the following:

• In a majority of cases, removal of the cyst is not necessary, unless the cyst causes bothersome signs and symptoms such as cosmetic issues
• The treatment of choice is a complete surgical excision, which results in a cure
• Proliferating Trichilemmal Cysts should be excised completely, since they can infiltrate into surrounding tissue and damage them

How can Trichilemmal Cyst be Prevented?

Currently, there are no known methods available to prevent the occurrence of Trichilemmal Cysts.

What is the Prognosis of Trichilemmal Cyst? (Outcomes/Resolutions)

The prognosis for Trichilemmal Cyst is excellent with appropriate treatment, since it is a benign cyst.

Additional and Relevant Useful Information for Trichilemmal Cyst:

• There is no evidence to prove that oily foods and chocolate-based products have an influence on Trichilemmal Cyst
• Cleaning the skin too hard with strong chemicals or soaps may aggravate the skin condition. Care must be taken avoid strong soaps and chemicals that could potentially worsen the condition
• The presence of dirt on the body is not a causative factor for the condition. However, it helps to be clean and hygienic, which may help the condition from getting worse