Even before there were demonolgists or even Christians, Muslims and Jews, we had "hellhounds" of one sort or another. Greek myths had them as companions to the Goddess Hecate. Likewise the Norse had them as companions to the Goddess Hel. The also, respectively, featured unique hounds like Cerberus and Garm that guarded the gates of the afterlife.
Hellhounds though also are also popular in popular literature. The most popular story of a hell hound was Sherlock Holmes and the Hound of the Baskervilles. Though it could have been more about a Black Dog or even Black Shuck. In the end it wasn't any of those of course.
Dogs of course are one of humanity's oldest companions. When we were just figuring out what to do with civilization, dogs were there with us. They have evolved much as we have. As a psychologist and atheist I find it very fascinating that we can demonize them so. As a gamer I find them equally as fascinating.
Hellhounds were introduced to the D&D game back in the earliest days in the Greyhawk supplement to the Original D&D rules. This book included another dog-like creature, the Blink Dog, which seems to be the "good" counterpart. They appeared next in the classic Monster Manual and have been in every edition of the game ever since.
Given the horror aspect, and out of respect to ACD, here is the hell hound for various game systems, but focusing on Victorian age ones.
Ghosts of Albion, Unisystem
Creature Type: Demonic Animal
Life Points: 30
Drama Points: 1
Muscle: 14, Combat: 14, Brains: 5
Special Abilities: +10 to Brains Score for smell and hearing sensing, Demon, Fear, Hard to Kill, Lesser Sensing, Cold Vulnerability, Breathe Fire, Resistance (Fire).
Anyone seeing a Hellhound for the first time must make a Fear check (Willpower x2).
Hellhound do not take damage from fire but take double damage from cold.
Name Score Damage Notes
Bite +14 11 Slash/stab
Fire Breath +14 15 fire* (extra fire damage based on SL)
Deflect +9 - Magic defence action; deflects spell 45˚
Savage Worlds (Rippers / Gaslight)
Attributes: Agility d8, Smarts d4, Spirit d6, Strength d10, Vigor d8
Skills: Fighting d8, Guts d8, Notice d8, Stealth d6, Survival d4, Tracking d10
Pace: 8; Parry: 5, Toughness: 9
• Bite: Str+2
• Breathe Fire: A hellhound can breath a jet of flame that causes fire damage (Spirit +2)
• Fear: Anyone that sees a hellhound must make a Guts roll.
• Fleet Footed: Hellhounds have a d10 running die.
• Go for the Throat: If a Hellhound gets a raise on its attack roll, it strikes its opponent’s least armoured location.
• Resistance (Fire): Hellhounds take n damage from fire.
• Weakness (Cold): Hellhounds take +4 damage from cold or cold based weapons.
Victoriana 2nd Edition
Rank: 2 (Generalist)
Physical competence: 6
Mental competence: 4
Health: 5 (10)
Signature Skills: Conceal +5, Hide & Sneak +5, Perception +5,
Traits: Fire immunity, Night Vision
Armour: 1 (thick fur)
Combat Abilities: Bite (2 dice), Breath Weapon (3d)
Damage: Bite (3d), Fire (4d)
Victoriana 1867 Edition
Physical Competence: 15
Health: 35/15 (surrounded by flames)
Skill Picks: Hide & Sneak (10), Dodge! (8)
Combat Picks: Bite 2d+4 lethal (10), Gaze (8) – opposed roll against opponent’s resolution, or the target is stunned for 2 rounds, Breath Fire (10) for 4d+4.
Hellhounds are 1st circle demons, slightly above imps.
Basic Era D&D / The Witch (because I can)
Armor Class: 3 
Hit Dice: 4d8+4* (22 hp)
No. of Attacks: 2 claws / 1 bite / breath weapon
Damage: 1d4 / 1d4 / 1d6+3 / 1d8 (fire)
Special: fear, low-light vision (120’), scent
No. Appearing: 1 (1-3 in lair)
Saves As: Fighter 5
Hellhounds cause fear as per the spell (Save vs. Paralysis to negate). They also breathe out a lick of flame while attacking, save vs Breath Weapon for half-damge.
Five systems is pretty good. That's a whole pack of hellhounds.