pell-mell vs helter-skelter

pell-mell and helter-skelter both are adjectives.

Word	Noun	Adjective	Verb	Adverb
pell-mell	No	Yes	No	Yes
helter-skelter	No	Yes	No	Yes

As adjectives, pell-mell and helter-skelter are synonyms defined as:

pell-mell (adjective)	helter-skelter (adjective)
with undue hurry and confusion	lacking a visible order or organization
	with undue hurry and confusion

pell-mell (adverb)	helter-skelter (adverb)
in a wild or reckless manner	haphazardly