What is the treatment for a fire ant (Solenopsis invicta) bite?

From the Guidelines

To treat a fire ant bite, immediately wash the area with soap and water to remove any venom, apply a cold compress for 10-15 minutes to reduce swelling and pain, and consider using oral antihistamines and analgesics to reduce itching and pain associated with cutaneous reactions, as recommended by the 2011 practice parameter update on stinging insect hypersensitivity 1. The treatment for a fire ant bite typically involves measures to reduce local pain and swelling, as well as preventing secondary infection.

• Wash the area with soap and water to remove any venom
• Apply a cold compress for 10-15 minutes to reduce swelling and pain
• Use oral antihistamines, such as diphenhydramine (Benadryl) 25-50mg every 4-6 hours or cetirizine (Zyrtec) 10mg once daily, to control itching and allergic reactions
• Take analgesics, such as acetaminophen (Tylenol) 325-650mg every 4-6 hours or ibuprofen (Advil) 200-400mg every 6-8 hours, to help with pain
• Avoid scratching the bite to prevent infection It is essential to note that fire ant stings can cause a sterile pseudopustule within 24 hours, which should be left intact and kept clean to prevent secondary infection, as stated in the 2011 practice parameter update on stinging insect hypersensitivity 1. In cases of large local reactions, prompt use of oral corticosteroids may be effective in limiting swelling, although this is based on limited evidence and should be considered on a case-by-case basis, as mentioned in the 2011 practice parameter update on stinging insect hypersensitivity 1. Immunotherapy with imported fire ant whole-body extracts may be recommended for patients who have experienced a systemic reaction to a fire ant sting and have positive skin test responses or allergen-specific serologic test results, as discussed in the 2011 practice parameter update on stinging insect hypersensitivity 2.

From the FDA Drug Label

Emergency treatment of allergic reactions (Type I), including anaphylaxis, which may result from allergic reactions to insect stings, biting insects, foods, drugs, sera, diagnostic testing substances and other allergens, as well as idiopathic anaphylaxis or exercise-induced anaphylaxis. The treatment for a fire ant (Solenopsis invicta) bite is epinephrine (IM), specifically for emergency treatment of allergic reactions (Type I), including anaphylaxis, which may result from allergic reactions to insect stings or biting insects 3.

• Key points: + Epinephrine (IM) is used for emergency treatment + Treatment is for allergic reactions (Type I) and anaphylaxis + Insect stings and biting insects are included as potential causes of allergic reactions.

From the Research

Treatment for Fire Ant Bites

The treatment for fire ant bites can vary depending on the severity of the reaction.

• For local skin responses, there is no specific medical regimen that can alter the clinical or pathologic course of the fire ant pustule 4.
• For allergic individuals, immunotherapy with fire ant whole-body extract can prevent serious recurrent systemic reactions 5, 6.
• Rush immunotherapy (RIT) with fire ant whole body extract has been shown to be safe and efficacious, with a low rate of mild systemic reactions 7.
• Premedication with antihistamines and steroids is not necessary, as it does not reduce the systemic reaction rate associated with RIT 7.
• Diagnosis of fire ant allergy can be made by the radioallergosorbent test (RAST) or by skin testing using fire ant whole-body extract 5, 6.

Prevention and Management

• Prevention and primary care treatment of fire ant stings involve avoiding areas where fire ants are common and using protective clothing 8.
• Patient education on the risks and management of fire ant stings is also important 8.
• Fire ant allergen-specific immunotherapy can reduce the risk of subsequent systemic reactions 6.