What is a lump that feels like a pea? A Guide to Causes and When to See a Doctor

October 2, 2025 •

4 min read

Approximately 1 in 1,000 people will develop a benign lipoma, but many other common conditions can cause a small, pea-sized bump. A lump that feels like a pea under the skin is a common occurrence and, while often harmless, can cause concern. Understanding the potential causes can help you determine the appropriate next steps.

Quick Summary

A pea-sized lump under the skin is often a benign growth like a cyst or lipoma, or a swollen lymph node reacting to an infection. Cysts are fluid-filled sacs, while lipomas are soft, fatty tissue masses. While most are harmless, it's wise to monitor them and see a doctor if they change or cause discomfort.

Key Points

Common Causes: Pea-sized lumps are often benign skin cysts, fatty lipomas, or swollen lymph nodes reacting to an infection.
Cyst vs. Lipoma: Cysts are firm, keratin-filled sacs, while lipomas are soft, rubbery, fat-filled lumps that move easily under the skin.
Swollen Lymph Nodes: These are common, temporary, and often tender, indicating your body is fighting an infection and will typically shrink as you recover.
When to See a Doctor: Seek professional medical advice for any new or changing lump, especially if it's hard, immovable, grows rapidly, causes pain, or bleeds.
Observation is Key: Harmless lumps can often be monitored, but a medical evaluation is the only way to get a definitive diagnosis and rule out more serious conditions.
Avoid Self-Treatment: Do not try to pop or squeeze a lump, as this can lead to infection, inflammation, or scarring; professional draining is the safer option.

Common Causes of a Pea-Sized Lump

Many different conditions can manifest as a small, pea-sized lump under the skin. Knowing the specific characteristics can often help in identifying the most likely culprit. However, a professional diagnosis from a healthcare provider is always recommended for certainty.

Benign Cysts

Benign cysts are one of the most frequent causes of small skin lumps. These are enclosed sac-like pockets in the skin that can be filled with fluid, pus, or other material. They are typically non-cancerous and grow slowly. Different types of cysts can appear, each with slightly different characteristics and locations:

Epidermoid Cysts: Also known as epidermal inclusion cysts, these are the most common type. They form when surface skin cells get trapped underneath the skin. Filled with keratin, they feel smooth to the touch and can sometimes have a central pore.
Pilar Cysts: Similar to epidermoid cysts but most often found on the scalp. These are also keratin-filled but arise from a hair follicle.
Ganglion Cysts: These are not skin cysts but rather form on a joint or tendon, most commonly on the wrists, hands, and fingers. They are filled with a jelly-like fluid and can sometimes feel pea-like.

Lipomas

A lipoma is a benign, slow-growing tumor made of fatty tissue. They are often found between the skin and the underlying muscle layer and are very common. They are typically:

Soft and doughy: Unlike a hard cyst, a lipoma has a softer, rubbery texture.
Movable: They move easily under the skin when gentle pressure is applied.
Painless: In most cases, lipomas do not cause pain unless they grow and press on a nearby nerve.
Located: Commonly found on the neck, back, shoulders, arms, and trunk.

Swollen Lymph Nodes

Part of your body's immune system, lymph nodes are small, bean-shaped glands found throughout the body, including the neck, armpits, and groin. When you're fighting an infection, your lymph nodes can swell up to a pea size or larger. This is a normal and temporary reaction.

Characteristics: Swollen lymph nodes often feel soft and movable. They might also be tender or sensitive to the touch.
Duration: They typically shrink back to their normal size as the infection subsides.
Accompanying symptoms: May occur alongside fever, fatigue, or other signs of illness.

Other Potential Causes

Beyond the most common culprits, other conditions can also cause a small, pea-sized bump:

Dermatofibromas: These are small, firm, round skin growths that often appear on the lower legs. They are benign and can feel hard or like a rock under the skin. They often dimple inwards when pinched.
Boils or Abscesses: These are painful, pus-filled lumps caused by bacterial infection of a hair follicle. They can be hard, warm, and red.
Keratosis Pilaris: This is a harmless skin condition that causes small, painless, sandpaper-like bumps, often on the upper arms, thighs, and cheeks.
Insect Bites: A sudden, raised, red lump can be a reaction to an insect bite or sting.

Cyst vs. Lipoma: Key Differences

While both cysts and lipomas are common, benign skin growths, they have distinct characteristics. A table provides a clear comparison:


Feature	Cyst	Lipoma
Composition	Enclosed sac filled with keratin (a protein), fluid, or pus.	Mass of fatty tissue.
Texture	Firm to the touch and can feel hard.	Soft, doughy, or rubbery.
Movement	Can be movable but often less mobile than a lipoma.	Moves easily under gentle finger pressure.
Sensation	Often painless unless it becomes inflamed or infected.	Typically painless unless it presses on a nerve.
Appearance	Can have a central pore or appear white/yellowish. May become red if inflamed.	Skin color typically unchanged. Smooth appearance under the skin.

When to Seek Medical Attention

While many pea-sized lumps are harmless, there are times when a medical evaluation is necessary to rule out more serious conditions. It is always wise to have a new or changing lump checked by a healthcare provider, especially a dermatologist. Concerns can arise if:

The lump is hard and feels fixed or immovable.
It grows rapidly or changes in size, shape, or color.
The lump is painful, red, warm, or inflamed.
It bleeds or discharges fluid.
The lump persists for more than a few weeks without signs of shrinking.
It appears in a specific location like the breast or testicle.
It is accompanied by other symptoms like fever, fatigue, or unexplained weight loss.

A professional can provide an accurate diagnosis, potentially with imaging tests or a biopsy, and discuss treatment options if necessary. For general health guidance, the National Institutes of Health offers reliable information on a wide range of medical topics.

Conclusion

Discovering a pea-sized lump can be alarming, but in many cases, it's caused by a common and benign condition such as a cyst, lipoma, or swollen lymph node. These are typically harmless and may not require treatment. However, paying close attention to its characteristics and monitoring for any changes is crucial. Consulting a healthcare provider for a proper diagnosis is the safest and most reliable course of action, ensuring peace of mind and appropriate care if needed.

Frequently Asked Questions

A cyst feels like a firm, round lump that may have a central pore and is filled with keratin (a protein). In contrast, a lipoma is a soft, doughy lump of fatty tissue that moves easily under the skin when you press it.

While most pea-sized lumps are benign (non-cancerous), in rare cases, they can be a sign of a more serious condition. It is important to see a doctor if a lump is hard, immovable, grows quickly, or is accompanied by other symptoms like unexplained weight loss or fever.

Swollen lymph nodes are often tender or sensitive to the touch, feel soft, and are movable. They typically appear in clusters in areas like the neck, armpits, and groin and are most commonly associated with a recent infection like a cold.

No, you should never attempt to pop or squeeze a lump yourself. Doing so can cause infection, inflammation, and scarring, and in the case of a cyst, it will likely return if the entire sac is not removed. A healthcare professional should handle any draining.

If a lump persists for more than a few weeks, grows, or changes in any way, you should see a doctor for an evaluation. Most harmless lumps from infections will resolve on their own, but prolonged or changing lumps warrant medical attention.

A dermatofibroma is a benign, small, hard growth that can appear on the lower legs and is caused by an accumulation of soft tissue cells. When you gently pinch the skin around it, a dermatofibroma will often dimple inward, which is a key distinguishing feature.

A pea-sized lump on the neck is very often a swollen lymph node due to an infection. If it persists, gets larger, or is accompanied by other worrying symptoms, it should be evaluated by a healthcare professional to rule out other issues, including rarely, certain cancers.