Can XYZAL Cause Mouth Sores?
XYZAL (levocetirizine) does not typically cause mouth sores as a recognized adverse effect, and this is not listed among its known side effects in clinical trials or pharmacological reviews. 1, 2
Evidence from Clinical Studies
The most comprehensive reviews of levocetirizine's safety profile do not identify oral ulcers, mouth sores, or stomatitis as adverse effects:
In large clinical trials spanning 6 months in adults with persistent allergic rhinitis, the most common adverse events were headache (23.8%), pharyngitis (19.4%), influenza (14.6%), fatigue (8.3%), and somnolence (8.3%)—with no mention of mouth sores or oral lesions 2
A systematic review of levocetirizine's pharmacological profile and clinical efficacy across multiple studies found it to be generally well tolerated, with an acceptable tolerability profile that did not include oral mucosal lesions 1
Pediatric studies comparing cetirizine and levocetirizine over 12 weeks similarly did not report mouth sores as an adverse effect 3
Rare Cutaneous Reactions
While mouth sores are not a typical side effect, levocetirizine can rarely cause:
Fixed drug eruption (FDE), a Type IV delayed hypersensitivity reaction affecting the skin, though this typically presents as cutaneous lesions rather than oral ulcers 4
This reaction is extremely rare and represents a paradoxical response to an antihistamine 4
Important Differential Diagnosis
If a patient taking XYZAL develops mouth sores, consider alternative explanations:
Viral infections (Coxsackievirus, herpes simplex, Epstein-Barr virus) are the most common causes of oral blisters and ulcerations 5
Bacterial pharyngitis (Group A Streptococcus) can cause pharyngeal inflammation but requires bacteriologic confirmation 5
Fungal infections (oropharyngeal candidiasis) present as creamy white plaques, particularly in immunocompromised patients 5
Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis is a medical emergency characterized by painful mucosal blistering, but this is not associated with levocetirizine and typically follows exposure to sulfonamides, anticonvulsants, or allopurinol 6, 5
Clinical Recommendation
If mouth sores develop while taking XYZAL, investigate other causes rather than attributing them to the medication. The temporal relationship between drug initiation and symptom onset should be carefully evaluated, but given the absence of this adverse effect in the literature, alternative etiologies are far more likely 5, 1, 2