A pilar cyst is a non-cancerous growth developing within the skin, originating from the outer root sheath of a hair follicle. These cysts are also known as trichilemmal cysts or wens. They occur in less than 10% of the population but are the most common type of skin cyst found on the scalp.
Understanding Pilar Cysts
Pilar cysts are slow-growing, firm, smooth nodules that present as dome-shaped bumps under the skin. They are filled with keratin, a protein found in hair, skin, and nail cells. Although they can appear on the face, neck, or arms, over 90% of pilar cysts are found on the scalp.
For most people, these growths are asymptomatic, causing no pain or discomfort. They are mobile and flesh-colored, often going unnoticed until they reach a certain size. The cyst grows as old skin cells and keratin accumulate within the blocked follicle.
Investigating the Link Between Cysts and Headaches
A pilar cyst in its typical, non-inflamed state does not cause a generalized headache. The cyst is a superficial growth located in the skin layers of the scalp, and it does not directly affect the structures inside the skull, such as the brain or its surrounding membranes. The presence of the cyst alone is not enough to generate widespread head pain.
The connection between the cyst and head pain arises when the growth becomes complicated. If the cyst ruptures or becomes infected, it triggers an inflammatory process in the surrounding tissue. This leads to localized pain, swelling, and tenderness at the site, which can be perceived as focal head pain.
In rare instances, a very large cyst may cause localized pressure discomfort. This pressure is felt on the scalp tissue itself, not as a deep headache, unless the cyst is situated over a bony prominence or near a nerve. For example, a cyst on the back of the head might press on the occipital nerve, causing referred pain that travels up and over the head.
Another indirect link is the possibility of muscle tension. The anxiety or stress associated with having a visible lump on the head may lead to muscle tension in the neck and scalp. This secondary tension can contribute to the development of a tension-type headache.
Management and Relief
Because pilar cysts are benign and often asymptomatic, treatment is not always necessary, and watchful waiting is common. However, if the cyst causes discomfort, grows in size, or becomes painful, removal may be recommended. Attempting to drain or “pop” the cyst at home is discouraged, as this increases the risk of infection and inflammation.
If the cyst becomes infected, a healthcare provider may prescribe oral antibiotics to reduce swelling and inflammation. This alleviates the localized pain that may be mimicking a headache. Once the infection subsides, the cyst can be surgically removed.
The definitive treatment for a symptomatic cyst is surgical excision, which involves removing the entire cyst wall or sac. This complete removal prevents the cyst from returning and is effective at resolving the source of the pain. Successful treatment of the cyst should eliminate any related localized head pain or perceived headache.