Spreading Ailments | PoE2 Mechanic

What Spreading Ailments does

Current rules

When an effect spreads an Ailment, it inflicts a new Ailment of the same type on another target and keeps the original source. The new Ailment can spread again, but it cannot return to a target already visited in that spread chain. The entity that originally inflicted the Ailment can never be a spread origin or destination.

Spread creates a new matching Ailment: The destination receives a new Ailment matching the type that spread. This is not the original Debuff moving from one target to another.
The source remains the same: The new matching Ailment is attributed to the same source as the original Ailment. A later target spreading it again does not become its original inflicter.
A target cannot be visited twice: A newly spread Ailment can continue spreading, but that spread chain can never return to the same target twice. This prevents two nearby targets from passing one Ailment back and forth.
The original inflicter is excluded: Ailments cannot spread to or from the entity that originally inflicted them. This restriction applies even if that entity is inside the effect's stated range.
Range, delay, and trigger come from the source: The generic Spread definition supplies no universal radius, delay, or trigger. Wildfire and current Ignite-spread items use 1.5 metres and a 1 second stay, while Herald of Plague spreads Poison when a Poisoned enemy is killed.

Current ways Ailments spread

6 cases

01

Wildfire

Wildfire supports a Skill that Hits and makes Ignites inflicted by that Skill spread to enemies that stay within 1.5 metres for 1 second.

Related: Wildfire, Ignite, Hit

02

Cracklecreep

Ignites you inflict spread to other enemies that stay within 1.5 metres for 1 second. The ring does not make every other Ailment spread.

Related: Cracklecreep, Ignite

03

The Searing Touch

Ignites you inflict spread using the same 1.5 metre and 1 second stay condition. Its increased Ignite Magnitude is a separate modifier from the Spread rule.

04

Herald of Plague

Killing a Poisoned enemy spreads its Poison to nearby enemies and can also Hinder them. This uses a kill trigger rather than the Ignite proximity delay.

Related: Herald of Plague, Poison

05

Fan The Flames II

Hits from supported Wind Skills against Ignited enemies trigger a fiery explosion. That explosion spreads the initial enemy's Ignite to other enemies hit by it.

Related: Fan The Flames II, Ignite, Hit

06

Phantasmal Arrow

Igniting an enemy with the delayed explosion also applies Ignite to enemies in range. This is a Skill-specific area application and should be read from that Skill rather than treated as the universal Spread trigger.

Related: Phantasmal Arrow, Ignite

Limits and exceptions

6 rules

Spreading does not move the original Debuff away from its current target.
The generic definition does not provide a universal radius, delay, death trigger, or proximity requirement.
A spread chain cannot visit the same target twice.
The entity that originally inflicted the Ailment cannot be a spread origin or destination.
An effect that spreads Ignite does not also spread Poison, Bleeding, or non-damaging Ailments unless its wording says so.
Check the source effect when exact Magnitude, duration, and trigger timing matter.

Related pages

9 connections

mechanicAilments

Ailments are damage-type-related debuffs: Bleeding, Ignite, Chill, Freeze, Shock, Electrocute, and Poison. Some deal damage over time, while others impair the target.

mechanicIgnite

Ignite is a damaging Elemental Ailment that deals Fire damage over time for four seconds by default. A Hit's chance to Ignite comes from the target's total Flammability, including Flammability applied by that same Hit.

mechanicPoison

Poison is a damaging Ailment that deals Chaos damage over time and bypasses Energy Shield. It lasts two seconds by default and requires an explicit chance or effect that can inflict Poison.

supportWildfire

Supports any skill that Hits enemies, Spreading Ignites it inflicts to nearby enemies after a delay.

unique itemCracklecreep

(20-30)% increased Fire Damage

unique itemThe Searing Touch

(80-120)% increased Fire Damage

skillHerald of Plague

While active, killing a Poisoned enemy spreads its Poison to other nearby enemies, and has a chance to also Hinder them.

supportFan The Flames II

Supports Wind Skills which Hit enemies. Hits with Supported Skills against Ignited enemies Trigger a fiery explosion, dealing damage to that enemy and enemies in a cone behind them. The explosion Spreads the initial enemy's Ignite to other enemies Hit.

skillPhantasmal Arrow

Fires an arrow that embeds where it lands for a short duration. At the end of the duration, the arrow explodes in spectral flame, turning it to ashes and damaging enemies, with a high chance to Ignite. Igniting any enemy with the Explosion also applies Ignite to enemies within range.

Items and gems using this mechanic

6 connections

Direct relationCracklecreep

(20-30)% increased Fire Damage

Direct relationFan The Flames II

Supports Wind Skills which Hit enemies. Hits with Supported Skills against Ignited enemies Trigger a fiery explosion, dealing damage to that enemy and enemies in a cone behind them. The explosion Spreads the initial enemy's Ignite to other enemies Hit.

Direct relationHerald of Plague

While active, killing a Poisoned enemy spreads its Poison to other nearby enemies, and has a chance to also Hinder them.

Direct relationPhantasmal Arrow

Fires an arrow that embeds where it lands for a short duration. At the end of the duration, the arrow explodes in spectral flame, turning it to ashes and damaging enemies, with a high chance to Ignite. Igniting any enemy with the Explosion also applies Ignite to enemies within range.

Direct relationThe Searing Touch