Skin cysts are closed sacs beneath or within the skin. Epidermoid cysts commonly affect the face, neck and trunk, while pilar cysts frequently develop on the scalp. They contain keratin rather than liquid and are usually benign. A cyst may remain unchanged for years, enlarge gradually or become inflamed, painful and infected.

What does a cyst look and feel like?

A cyst often feels smooth, round and firm, with the skin moving less freely over it than over a lipoma. A central opening may be visible. The lump can release thick, pale and strong-smelling material if it ruptures. Redness, heat, tenderness and rapid swelling suggest inflammation or infection.

Why do cysts recur?

The cyst wall continues to produce keratin. If the contents are squeezed out or drained but the lining remains, the lump can refill. Rupture can trigger a strong inflammatory response and make later surgery more difficult. A repeatedly discharging lump in another location may represent a sinus or a different skin condition rather than a simple cyst.

Diagnosis

Most cysts are diagnosed clinically. Ultrasound may help for a deep, unusual or uncertain lesion. A rapidly growing, ulcerated, repeatedly bleeding or irregular lump may require biopsy or a different referral pathway. Tissue removed during surgery is commonly sent for histology.

Treatment options

A quiet cyst that causes no problems may be observed. Complete excision removes the cyst and its wall and offers the best chance of preventing recurrence. An acutely infected cyst may first need antibiotics or incision and drainage. Definitive removal is often delayed until inflammation has settled.

Possible risks

Excision can cause bleeding, infection, wound separation, numbness and a permanent scar. Recurrence is possible if the cyst wall cannot be removed completely. Scalp wounds may occasionally affect a small area of hair growth.

Frequently asked questions

Is a skin cyst dangerous? Most are benign, but unusual or changing lesions should be assessed.

Should I squeeze a cyst? No. Squeezing can rupture the wall, cause inflammation and increase infection risk.

Can an infected cyst be removed immediately? Sometimes drainage is safer first, followed by excision after infection settles.

Will previous mesh need to be removed? Not usually. Removal is considered only when clinically necessary.