What Bit or Stung Me? Common Insect Injuries in Cancun and How to Treat Them

You wake up with mysterious welts on your leg. Or you swim in the ocean and get hand-shaped marks across your skin. Or you spend time at a beach bar and suddenly have blisters appearing hours later. In Cancun, "what bit/stung me?" is a common question. Here's a guide to identifying common culprits and treating them.

Jellyfish Stings (Most Common)

Identification

• Appearance: Linear or tentacle-like welts, often in straight lines or patterns
• Location: Usually on legs, arms, or any exposed skin that was in the water
• Timeline: Can appear immediately in water or hours later (especially with certain species like man-o-war)
• Symptoms: Burning sensation, blistering, swelling that worsens over hours

What Causes It

Jellyfish are most common May-October, with peak season August-September when waters are warmest. However, they can appear year-round. Man-o-war jellyfish are particularly problematic and often don't feel like a sting until you're out of the water and notice the marks.

Treatment

• Rinse with vinegar (if available at the beach)
• Soak in hot water (as hot as you can tolerate, 110-113°F) for 20-45 minutes
• Remove tentacle pieces carefully with tweezers
• Don't rub the area or use fresh water initially
• Take antihistamines or ibuprofen for itching and swelling
• Avoid scratching (easier said than done)
• See a doctor if blistering is severe or you have systemic symptoms

Prevention

• Check beach conditions before swimming
• Wear a protective suit or rash guard
• Ask locals if jellyfish have been spotted recently
• Avoid murky water where you can't see clearly
• Some beaches are netted to reduce jellyfish encounters

Phytophotodermatitis (Margarita/Lime Burn)

Identification

• Appearance: Hand-shaped or finger-like marks, usually on legs or chest
• Pattern: Looks like someone wiped their hand on your skin
• Timing: Appears after sun exposure following lime contact
• Progression: Starts as redness, progresses to blisters and severe burns
• Scars: Can last months after the acute phase heals

What Causes It

Lime juice (from drinks, food, or bar activities) combined with intense UV sunlight creates a chemical burn. You get lime on your hands, wipe it on your legs without thinking, and the tropical sun does the damage. Happens frequently to:

• Bartenders and server staff at beach bars
• People enjoying cocktails poolside
• Anyone handling fresh limes for food prep

Treatment

• Wash immediately with soap and water
• Apply aloe vera or burn cream
• Avoid sun exposure on the affected area
• Wear high-SPF sunscreen (SPF 50+) on the burn
• Take ibuprofen for pain
• Use CeraVe or similar healing creams for faster recovery
• Scars may fade over weeks to months with consistent sunscreen use

Prevention

• Wash hands immediately after handling limes
• Avoid wiping hands on your legs or body
• Wear sunscreen everywhere, not just obvious areas
• Be extra careful if mixing drinks at a beach bar
• If you get lime on your skin, rinse thoroughly before sun exposure

Fire Coral Stings

Identification

• Appearance: Welts and blisters on contact areas
• Sensation: Immediate stinging or burning in water
• Symptoms: Rash, welts, sometimes systemic itching
• Difference from jellyfish: You typically feel it immediately while in contact

What Causes It

Fire coral looks like coral but is actually a hydroid. It causes immediate stinging on contact. Less common than jellyfish but can be found in reef areas.

Treatment

• Rinse with vinegar
• Soak in hot water
• Apply hydrocortisone cream or antihistamine
• Don't scratch
• See a doctor if the reaction is severe

Sea Nettle and Other Stinging Creatures

Identification

Similar to jellyfish stings but may have slightly different patterns. Some species only sting when you step on them or brush against them unexpectedly.

Treatment

Similar to jellyfish: vinegar, hot water soaks, antihistamines, and avoiding scratching. Heat therapy (hot water) is the most effective treatment for most stings.

Mysterious Welts and Unexplained Rashes

Possible Causes

• Mosquitoes: Common in tropical areas, especially dawn and dusk
• Sand fleas: Rare but possible, cause itchy bumps
• Heat rash: Common in tropical humidity
• Allergic reactions: To sunscreen, insect repellent, or local plants
• Chiggers: Rare in resort areas but possible in vegetation

Treatment

• Hydrocortisone cream for itching
• Antihistamines
• Calamine lotion
• Ice packs for swelling
• See a doctor if it worsens or spreads

When to See a Doctor

Seek medical attention if you experience:

• Severe swelling that affects breathing or vision
• Systemic symptoms (fever, chills, nausea)
• Severe blistering or signs of infection (pus, increasing redness)
• Stings that don't improve in 24-48 hours
• Multiple stings or large affected areas

Prevention Tips for All Scenarios

• Protective clothing: Rash guards and wetsuits protect against most stings
• Be aware: Check local conditions before swimming or water activities
• Sunscreen: SPF 50+ everywhere, not just obvious areas
• Hand hygiene: Wash immediately after food prep, lime drinks, or sun exposure activities
• Footwear: Wear water shoes or sandals on beaches and in shallow water
• Stay informed: Ask hotel staff or locals about current beach conditions

The Bottom Line

Most bug bites and stings in Cancun are jellyfish or lime burns. The good news: both are treatable and rarely cause permanent damage if handled correctly. The bad news: they can be uncomfortable and annoying. Proper prevention (sunscreen, protective clothing, hand washing) goes a long way. If you do get stung, resist the urge to scratch, use hot water for jellyfish, and seek medical help if symptoms worsen.

Welcome to tropical beach life—where the sun is gorgeous and the welts are mysterious!