Reaction profile
The FDA adverse-event record for lymphocytosis
1,114 FDA reports name lymphocytosis, a high-volume reaction in the CVM extract (VeDDRA 165). Plate stamps and neighbourhood peers follow.
- #361 of 2,481
- by report volume (all reactions)
- 1,114
- reports citing this reaction
- 23.4%
- death-coded share
- Dog
- most-affected species
Release-over-release change
What changed in the latest FDA data snapshot
PlainBreed reconstructed the prior snapshot from dated openFDA partitions through 2025 Q4, then compared it with the 2026-07-27 openFDA export. Lymphocytosis has 1,114 reports now versus 1,084 in that prior snapshot: 30 more (2.8%).
- Report change
- +30
- Death-coded reports
- +9
- Death-coded share
- +0.2 pts
This compares reported-event counts in two source snapshots. It does not establish a change in real-world risk, product safety, or disease incidence.
Subscribe to Lymphocytosis changesFDA AER · VeDDRA plate
Code 165 VOL-MID
VOL-MID · DEATH-HOT · UPPER-Q · PHOTO-FINISH · SPECIES-DOG · DRUG-LEAD · DESK-WIDE · BOOK-FULL
- VOL-MID 1,114 reports
- DEATH-HOT 23.4%
- UPPER-Q #361/2481
- PHOTO-FINISH Inappropriate schedul…
- SPECIES-DOG Dog · 916
- DRUG-LEAD Milbemycin Oxime… · 124
- DESK-WIDE 20 breeds
- BOOK-FULL 8/8 fields
Nearest volume peer: Inappropriate schedule of drug administration (±1 reports)
Upper-third report volume drives the scale stamps on this plate; death-coded share and co-report peers follow. Not a clinical diagnosis.
High-volume neighbourhood around Lymphocytosis
Upper-third volume poles plus nearest peers, not a full reaction corpus board reprint.
What the FDA AER plate says about Lymphocytosis
Signature read: 261 death-coded reports is a heavy tail count for Lymphocytosis in the CVM extract. Report volume is upper-third scale: 1,114 named reports in the openFDA extract. 261 of 1,114 reports were death-coded (23.4% of named reports, not a population mortality rate). Nearest volume peer: Inappropriate schedule of drug administration (±1 reports). Lead species Dog (916). Lead co-reported drug Milbemycin Oxime + Spinosad (124).
Read these counts as reporting volume, not risk: per our methodology, Lead co-reported drug Milbemycin Oxime + Spinosad appears in filings alongside this reaction; that is association, not causation. Browse the full reactions index or the about page for how PlainBreed frames FDA CVM extracts.
Species Most Affected
Breeds Most Affected
Associated Drugs
Nationwide reactions with similar profiles
Two openFDA-derived peer sets for Lymphocytosis, both floored at ≥50 reports so the neighborhoods stay in the advertised mass (the volume chart above is the unfloored photo-finish strip).
Similar report volume
Nearest other reactions by FDA report count (1,114 here).
Similar death-coded share
Nearest other reactions by death-coded share (23.4% here), distinct from the volume row.
What to do with this reaction
- Compare Lymphocytosis's report profile against similar reactions nationwide. See similar reactions
- Read how death-coded share differs from a mortality rate before drawing conclusions. Understanding adverse events
- Browse the full reaction directory to compare report counts across reaction types. All reactions
A report does not prove a drug caused the reaction; consult a veterinarian before acting on this data.
Source: FDA Center for Veterinary Medicine openFDA Animal & Veterinary Adverse Events (CVM AER) · 2025
Informational only. FDA adverse-event reports are voluntary and do not prove causation; consult a veterinarian before acting on them. Verify with FDA CVM →