ΔE 14.3, fair: the same colour family, but not a straight swap. Sickly Skin is a little lighter, more saturated, cooler than Screaming Skull.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Sickly Skin is a little lighter, more saturated, cooler than Screaming Skull.
The same difference applies the other way round: Screaming Skull is a little darker, more muted, warmer.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Screaming Skull on the colour wheel See Sickly Skin on the colour wheel
All matches: Screaming Skull equivalents · Sickly Skin equivalents