diff --git a/common/spdat.h b/common/spdat.h
index a427a1126..10c8f8103 100644
--- a/common/spdat.h
+++ b/common/spdat.h
@@ -205,6 +205,9 @@
 #define SPELL_VAMPIRIC_EMBRACE 821
 #define SPELL_VAMPIRIC_EMBRACE_OF_SHADOW 822
 
+// discipline IDs.
+#define DISC_UNHOLY_AURA 4520
+
 //spellgroup ids
 #define SPELLGROUP_FRENZIED_BURNOUT 2754
 #define SPELLGROUP_ILLUSION_OF_GRANDEUR 38603
diff --git a/zone/spells.cpp b/zone/spells.cpp
index 612aae0d3..0ea0c5108 100644
--- a/zone/spells.cpp
+++ b/zone/spells.cpp
@@ -5127,6 +5127,12 @@ float Mob::ResistSpell(uint8 resist_type, uint16 spell_id, Mob *caster, bool use
 		}
 	}
 
+	// Special case. If the caster has the Unholy Aura Discipline activated and the spell is HT,
+	// or improved HT then the resist type is disease.
+	if ((spell_id == SPELL_HARM_TOUCH || spell_id == SPELL_HARM_TOUCH2 || spell_id == SPELL_IMP_HARM_TOUCH) && caster->IsClient() && caster->CastToClient()->FindBuff(DISC_UNHOLY_AURA)) {
+		resist_type = RESIST_DISEASE;
+	}
+	
 	//Get the resist chance for the target
 	if(resist_type == RESIST_NONE || spells[spell_id].no_resist)
 	{