What is the suitable action for a 23-year-old girl with a small bulla (blister) on her forearm, resulting from a mosquito bite one week ago, presenting with itching but no signs of infection, such as redness, hotness, throbbing pain, or fever?

Management of Small Bulla from Mosquito Bite

The most appropriate treatment for this patient with a small bulla from a mosquito bite with itching but no signs of infection is antihistamines (option B).

Clinical Assessment

This 23-year-old female presents with:

• Small bulla (1 x 0.5 cm) on forearm
• History of mosquito bite one week ago
• Itching as the primary symptom
• No signs of infection (no redness, hotness, throbbing pain, or fever)

Treatment Approach

First-line Treatment

• Oral antihistamines are the treatment of choice for local itching from insect bites 1
• These medications will effectively manage the pruritus which is the patient's primary complaint

Blister Management

• The small bulla should generally be left intact if possible to prevent secondary bacterial infection 1
• If the bulla is causing discomfort or is in a location where it interferes with function, it can be pierced with a sterile needle to drain the fluid while leaving the blister roof in place as a natural dressing 1

Supportive Measures

• Cold compresses may be applied to reduce local itching 1
• Application of a bland emollient (such as 50% white soft paraffin and 50% liquid paraffin) can support barrier function and encourage re-epithelialization 1

Why Other Options Are Not Appropriate

1. Antibiotics (Option A): Not indicated as there are no signs of infection (no redness, hotness, throbbing pain, or fever) 1. The 2024 AHA guidelines specifically note that antibiotics are usually not necessary for insect bite reactions without evidence of infection.

2. Incision and drainage (Option C): Too aggressive for a small, non-infected bulla. Guidelines recommend preserving the blister roof as a biological dressing 1. If drainage is needed, simple piercing with a sterile needle is preferred over incision.

3. Debridement (Option D): Completely inappropriate for a non-infected, non-necrotic lesion. This would be unnecessarily traumatic and could lead to scarring and secondary infection.

Special Considerations

• Monitor for signs of secondary infection (increasing redness, pain, purulence)
• If severe local reactions recur with future bites, the patient may consider carrying emergency epinephrine, though this is generally reserved for those with history of systemic reactions 1
• Rare cases of severe mosquito bite allergy can occur but typically present with much larger bullae, ulceration, or systemic symptoms, which this patient does not have 2, 3, 4

Follow-up

• No specific follow-up is needed if symptoms resolve with antihistamines
• Patient should return if signs of infection develop or if the bulla enlarges significantly