What Is Reef Rash and How Do I Treat It?

Reef rash is a skin irritation or allergic reaction caused by direct contact with coral mucus, slime, or toxins—especially from zoanthids and palythoa, which can contain dangerous palytoxin. The severity ranges from mild itching to serious medical emergencies requiring hospital care.

Symptoms of Reef Rash

Symptoms typically appear within minutes to hours after exposure:

• Mild cases: Redness, itching, slight burning sensation
• Moderate cases: Raised welts, persistent irritation, swelling
• Severe (palytoxin): Intense pain, numbness, difficulty breathing, chest tightness, fever

How to Treat Reef Rash

For Mild Reactions

1. Remove contamination immediately: Rinse affected area under running water for 10-15 minutes
2. Apply vinegar: Soak the area in white vinegar to neutralize toxins (do NOT use hot water, which can increase toxin absorption)
3. Wash with soap: Gently clean with mild soap after vinegar treatment
4. Apply topical cream: Use hydrocortisone cream or antihistamine cream to reduce itching and inflammation
5. Take oral antihistamines: Benadryl or similar can help with allergic reactions

For Severe Reactions (SEEK MEDICAL HELP)

Call 911 or go to the emergency room immediately if you experience:

• Difficulty breathing or shortness of breath
• Chest pain or tightness
• Fever, chills, or muscle weakness
• Severe swelling or spreading rash
• Numbness or tingling beyond the contact area
• Nausea, vomiting, or dizziness

Tell medical staff you've been exposed to marine coral toxins, possibly palytoxin. This information is critical for proper treatment.

Which Corals Cause Reef Rash?

While any coral can cause skin irritation, these are the most problematic:

• Zoanthids and Palythoa: Can contain deadly palytoxin—the most dangerous
• Euphyllia (torch, hammer, frogspawn): Have potent stinging cells
• Anemones: Powerful nematocysts that can sting
• Acropora and Montipora: Mucus can irritate sensitive skin

Prevention Tips

The best treatment is prevention. Always follow these safety practices:

• Wear gloves: Use nitrile or latex gloves when handling any coral
• Eye protection: Wear safety glasses when fragging—aerosolized toxins can cause severe eye damage
• Work in ventilated areas: Never frag zoanthids or palythoa in enclosed spaces
• Don't touch your face: Avoid touching eyes, nose, or mouth until hands are thoroughly cleaned
• Cover cuts: Open wounds absorb toxins faster—bandage any cuts before tank maintenance
• Wash immediately: Clean hands and arms after any tank work, even if you wore gloves

Special Warning About Palytoxin

Palytoxin is one of the most toxic organic compounds known. It can be absorbed through skin, inhaled as vapor when corals are stressed or boiled (don't boil live rock with zoas!), or enter through eye contact. Symptoms of palytoxin poisoning include:

• Metallic taste in mouth
• Muscle spasms and weakness
• Respiratory distress
• Heart complications

While serious palytoxin cases are rare, they do happen. Several reefers have been hospitalized after improper handling of zoanthids. When in doubt, treat every zoa as potentially dangerous.

When to See a Doctor

Consult a healthcare provider if:

• Symptoms don't improve within 24-48 hours
• Rash spreads or worsens
• You develop signs of infection (increased redness, pus, warmth)
• You experience any systemic symptoms (fever, muscle aches, breathing issues)

Stay safe while enjoying the hobby! For more coral handling tips, check out our fragging guide and always use proper protective equipment when working with your reef tank.