Excel 2013 : Conditional Formatting consecutive Duplicate in 1 column

Question

I'm using Excel 2013 and I have a column with 30,000 items. Below is sample format of items , now using Conditional Formatting I wanted to highlight only consecutive columns where count > 2. I tried Conditional Formatting->Highlight Cells Rules ->Duplicate Values. It highlights all occurrences.
I Only want to highlight consecutive duplicate columns? .
Current requirement is not to use any additional columns but use existing column only.

ITEM 1
ITEM 2
ITEM 3
ITEM 3
ITEM 4
ITEM 5
ITEM 3
ITEM 2
ITEM 4
ITEM 4

Answer 1

To achieve:

Apply the Formula Is option to cell A1 with the formula:

=A1=A2

Then to A2 apply the Formula Is option with the formula:

=OR(A2=A1,A2=A3)

Then copy the formatting of A2 down the column.