Impetigo is a bacterial infection of the skin (caused by staph/strep) , so therefore it's treated with antibiotics. It's also very contagious and it's most common in children; same as HSV, spread by close contact. It also causes papules/blisters which generally heal without scarring.

Herpes: Herpes simplex virus, Rp: acyvclovir, eczema treated with corticosteroids

Herpes : herpes simplex virus, Rp: acyclovir eczema treated with corticosteriods

Well the first one is Herpes simplex virus or HSV, a virus from the same family as Varicella Zoster (the cause of chickenpox). HSV causes rashes/blisters and it's generally known as "cold sores" around the mouth/nose area (extremely contagious, you can get it through saliva on cups, kissing etc) or genital herpes (sexually transmitted disease, different strain of the virus). The cold sores can go away on their own in approx a week, but you can treat them with acyclovir and it's cousins (valacyclovir, famcyclovir) - cream/pill/injection. Lysine helps too (it's an aminoacid, high doses supposedly delay the evolution of the blisters *if taken right away). The fun thing about HSV is that you can have it in your system for years and it won't manifest. But then you go through a stressful period in your life, your immune system isn't working properly and boom, you have an unsightly son of a bitch on your face for a minimum of 7 days.

The aphthous ulcers are also known as canker sores. They're benign, not contagious and chronic (idk if it's the right term, the thing is they occur periodically, triggered by all sorts of things - diet , stress, local injury or trauma, immune-compromised patients, the presence of HIV/aids/celiac disease etc). As far as I know, the main treatment is topical corticosteroids combined with a more careful diet (no spices, acidic food etc) and good oral hygiene.

The last one is a type of eczema caused by allergies, on hands and feet (I sometimes get a really mild form of this during spring allergies, makes my fingers itchy af). Not contagious, also manifests by blistering, redness, treated by topical steroids and I think it can be somewhat prevented or controlled by moisturizing and proper skin care. I find these types of cases very interesting btw, because they can be triggered by a multitude of things which pretty much influence each other. Stress -> hormonal imbalances -> immune system and overall state of the human body, but then stress also doesn't stop at the mental/psychological part, it also means chronic conditions, sudden changes of environment, flying overseas and lots of other things.