Mosquito bite: INFECTION or Large Localized Reaction?

[ianson22]

Hey, guys! I sincerely hope you can help me properly diagnose this condition and establish an effective treatment.

Causes: after cycling for a couple of hours, I decided to take a short break in a mosquito-rich area. With my body warmed and having no insect repellent sprayed on it, my exposed legs became a feast for a bunch of hungry mosquitos. After the attack, I was left with 7-8 bites, one of which is the object of my worries.

Complication: although all the rest of the bites produced the usual tiny red bumps, one bite produced a flat purple area around itself (the center being the most saturated in color), even though I never scratched it. The reaction was delayed and it became noticeable the day after I was bitten. Within 48 hours a red rash started developing, gradually spreading to the sides and down to my ankle. Four days later, it has become 7" wide and 9" tall. It is non-palpable and blanching, also warm but no longer itchy. Occasionally, the area around the bite gets tight if I have been lying or resting my leg.

Photos: http://s1116.photobucket.com/user/ui945ls/library/Lesion

Initial treatment: I applied a layer of strong topical corticosteroid once daily during days 1 and 2. It had zero effect and did not slow down the process. Applying ice on the lesion soothed the itching and reduced the temperature, but the effect was only temporary.

Dermatological opinion: a dermatologist diagnosed me with a skin infection and prescribed tetracycline antibiotics.

Discussion

This is the second time I am experiencing the exact same problem this month. No anti-repellent -> mosquito bite -> small purple lesion -> large red rash and some swelling. While the first time I was convinced this was an infection, I am now in doubt of this diagnosis, having read about mosquito bite allergies and the lack of conclusive evidence on the effectiveness of topical creams and antihistidine drugs when treating bug bites. That said, I've been bitten by mosquitos all my life and never had such complications. More importantly, the last time I was bitten, only one of many bites produced a big rash, leading me to believe that I am not overly sensitive to mosquito saliva.

I remember a drop of blood around the bite at the time I was bitten, but it could have been due to me killing the mosquito while it was feeding. There definitely was a precedent for infection, but since this is the second occurrence in a month, I am worried this could be an allergic reaction.

Would you diagnose this problem as:

- a bacterial infection due to scratching / killing the mosquito while it was sucking blood
- a delayed large local area reaction due to a mild mosquito bite allergy
- a complication due to a bite from a disease-infected mosquito
- something else?

Thank you!

[Donnadesq]

Did you ever reach a conclusion?  I was in Mexico and was bitten by what I thought was mosquitos and have non-blanching discolorations on my hand and next to my eye.

[Life360_Dave]

Nasty little bugs! And that was interesting what the doctor said about recent infectious mosquitos!

[ianson22]

Thanks for your comment! I can confirm with almost 100% certainty this was a mosquito bite, because I was attacked by an army of mozzies when this happened. Also, this is the second time a complication develops from a mosquito bite while I was awake. Like I said, the rash was flat, very itchy and warm, but it also swelled a bit and occasionally felt stiff 2-5 days after the bite. The doctors' opinion is that this year multiple such cases have been registered due to disease-infected mosquitos. Granted, I still cannot determine whether the rash was due to a self-inflicted infection, external disease or oversensitization.

[Life360_Dave]

Hi and welcome. Did it hurt or itch? Looks like a bite from a spider, tick or other bug. Things that bite and leave running trails down the legs are more from a poison than typical mosquito numbing chemical.