Why do different kinds of bug bites itch in different ways?

Question

I have gotten bit by 3 different bugs that have all given me itchy bites but they are oh so different.

The most recent one is a tick bite, today is the first time I ever remember having a tick bite. I could not feel the tick at all until I felt my neck with my hand. It didn't suck much if any blood(how do I know? It looked deflated and alive after I grabbed it and pulled it off). It immediately started itching after I pulled the tick off but that itch is resolving. There is no swelling at the moment.

Mosquito bites are also from a blood sucking bug but this is way different. I actually once endured a full mosquito bite while awake at night. I can tell you from that experience, a mosquito bite is painless at first and then as it continues to suck blood it becomes painful, almost as though it injected venom. After the mosquito flies off nothing happens for several hours. But then it becomes irresistibly itchy(so I rub instead of scratch it) and is like that for a few hours at a time, several times a day.

Spider bites are even more different. Whether I am awake or asleep, the spider biting me is unnoticeable. Then a few hours later it is just like a mosquito bite but worse(again irresistibly itchy for a few hours at a time, several times a day but the itch is much worse.

So yeah, 3 bugs, all give itchy bites, but the bites are so different in timing and/or severity. No allergies to anything except pollen and pet dander. Why are they so different, especially the tick and mosquito which both suck on blood?

Answer 1

From what I remember, some biting insects deliver an anticoagulant . This may irritate, though it's not well studied. Others rely on not being detected, and deliver an anaesthetic.

One effect that can affect how much a particular bite irritates, even for the same species, is if you knock it off leaving mouthparts behind. Of course different parts of your body have differing sensitivities to stimulus, and are also irritated differently by clothing etc. (a cuff rubbing on a bite can be particularly annoying)

Answer 2

The cause of the itch can be quite different.

For mosquito bites, the itch is due to a allergic reaction to the mosquito's saliva. The strength of this allergic reaction varies between people, and it is possible, usually after enough exposure, to develop immunity. That means your body no longer over-reacts to the mosquito spittal.

Tick bites usually itch for long periods of time (it can take a month or more) because often a piece of the tick is left in your skin. The body attacking and breaking down this foreign stuff stuck in your skin includes processes that can cause itching.

There are various kinds of spider "bites". Some spiders actually feed on your skin. In that case the itch is similar to when a scab heals. It's part of the body's process of re-generating and healing tissue. Such spiders have evolved to inject anesthetic so that you don't feel it when they are feeding.

Other spiders inject venom. Different venoms can have different effects, from itching to resparatory failure or paralysis resulting in death.