Lumps, Bumps, and Swellings on Leopard Geckos: A Quick Guide

Found a weird bump on your leopard gecko? You’re not alone. Bumps and lumps can show up for all sorts of reasons—some harmless, others serious.

Let’s break down what these swellings might mean, what to watch for, and when to call a vet.

Common Causes of Lumps and Bumps

Your gecko’s skin is usually smooth. So when something bulges out, it’s easy to worry. Here are the most common reasons you might spot a bump:

Armpit Bubbles

If there’s a squishy lump near the armpit, it’s likely a calcium or fat deposit. These are common in healthy, well-fed geckos.

Most of the time, they’re nothing to stress about. But if they get big, hard, or start affecting movement, it’s time to reassess diet and consult a vet.

Abscesses

These are hard, swollen areas—usually red or warm to the touch. They’re caused by infections under the skin and need professional care.

Don’t try to pop or drain them at home. Your gecko needs antibiotics and possibly a vet to remove the pus.

Tumors and Cysts

A lump that grows over time could be a tumor (benign or cancerous) or a fluid-filled cyst. They might feel soft or firm.

There’s no way to tell what it is without a vet. The sooner you get it checked, the better the outcome.

Sperm Plugs or Swollen Hemipenes (Males)

If the bump is near the base of the tail or around the vent in a male gecko, it could be a sperm plug or impacted hemipenes.

These don’t usually go away on their own. A vet might need to remove the plug or flush the area to prevent infection.

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Fatty Deposits

Overfed geckos can develop soft bulges along the belly, neck, or armpits. These fat pockets aren’t dangerous, but they’re a sign your gecko might be eating too much.

Adjust the feeding schedule and cut back on fatty feeders like superworms.

Metabolic Bone Disease (MBD)

MBD can cause swollen limbs, misshaped bones, or a lumpy spine. It comes from a lack of calcium, vitamin D3, or UVB light.

If your gecko has trouble walking, looks floppy, or shows bone deformities, this could be the cause—and it needs vet care fast.

Vitamin Deficiencies

Lumps in strange places could come from low vitamin A or E, causing hard tissue or muscle damage.

These are less common, but worth mentioning—especially if you’ve been skipping supplements.

Egg Binding (Females)

A firm, swollen belly in a female gecko might be stuck eggs. This is called egg binding, and it’s a serious emergency.

If your gecko isn’t laying but seems bloated, uncomfortable, or refuses to eat—get to a vet now.

Injuries or Hernias

Sometimes swelling is due to an injury, internal bleeding, or a hernia, where organs push through weak muscles.

These often show up suddenly and may get worse fast. Don’t wait around—see a vet immediately.

Where the Bump Is Matters

Here’s a quick location-based guide to help you guess what’s going on:

Location	Possible Cause	Urgency
Armpits/Neck	Fat deposits, calcium bubbles, abscess	Low–High
Head/Jaw	Abscess, tumor, infection	High
Base of Tail/Vent	Sperm plugs, hemipenes, infection	Moderate–High
Belly/Abdomen	Egg binding, hernia, tumor, fat	High
Legs/Feet	MBD, trauma, cysts	High

What You Should Do

• Soft, squishy, non-painful bumps: Monitor them. These are often fat or calcium deposits. If they grow or get firm, call a vet.
• Hard, red, growing, or painful lumps: Don’t wait. These need a professional exam.
• Swelling with other signs (not eating, lethargy, odd poop): Treat it like an emergency.
• Take clear photos and write down when you first noticed the lump. This helps your vet a lot.

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Prevention Tips

Most of these issues link back to care. Here’s how to keep your gecko lump-free:

• Dust feeders with calcium and vitamin D3.
• Use a proper heat gradient (warm side around 88–92°F).
• Add UVB lighting—even for nocturnal geckos, it helps prevent MBD.
• Feed the right amount. Not too much. Not too fatty.
• Keep the tank clean to reduce infection risks.

When In Doubt, Call a Vet

If you’re unsure what you’re looking at, it’s always better to be safe. Some bumps are no big deal. Others are the first sign of something serious.

A reptile vet can check the lump, do a biopsy if needed, and tell you exactly what’s going on.