I'd suspect it was just cold damage. Cut back all the damaged portions and it will regrow.

I'll have to post a photo of the entire area looks because its so bad that it has to be something else.

Where are you located? Living in the Land English Ivy Ate, I can attest that virtually nothing bothers it. Unfortunately.

Mites can be a problem with ivy grown indoors but rarely affects outdoor plantings. They can get some fungal leaf spots that can disfigure the foliage (odd, it's never seen it here in the fungal capitol of the US) but cutting it back hard and clearing away the debris should suffice.

English ivy is an extremely tough and hardy plant. Generally the only things that cause it much distress are dry conditions in a lot of sun and cold winters in zone 6 or lower.

Another photo

This fence used to be covered in healthy green ivy.

Garden gal I'm ftom New Jersey in the states.

In the top picture the ivy looks as if it is in its arborescent phase. So it could do with a good haircut if it is invasive in your area and you want to get it back to the attractive-leaved climbing form.

your so lucky I have been fighting it for years , this year Im taking back my yard after it killed some 75 fott tall maple tress that fell on my house
lots of stump killer vine kller weedwacking weekly and tons of hand pulling and I got a mostly ivy free garden bed 10 x 40 ' long
and a few of hundreds of trees ivy free