Fixed Drug Eruption Due to Chlorhexidine Mouthwash Confirmed by Lesional Patch Testing

New Insights Regarding the Use of Relevant Synthetic Compounds in Dentistry

Worldwide, synthetic compounds are used for both in-office and at-home dental care. They are a valuable resource for both prophylactic and curative treatments for various dental problems, such as tooth decay, periodontal diseases, and many more. They are typically preferred due to their broad range of actions and ability to produce targeted, rapid, and long-lasting effects. Using a 0.12% chlorhexidine mouthwash is capable of reducing the plaque index from 47.69% to 2.37% and the bleeding index from 32.93% to 6.28% after just 2 weeks. Mouthwash with 0.1% OCT is also highly effective, as it significantly lowered the median plaque index and salivary bacterial counts in 152 patients in 5 days compared to a control group (p < 0.0001), while also reducing the gingival index (p < 0.001). When povidone-iodine was used as an irrigant during the surgical removal of mandibular third molars in 105 patients, it resulted in notably lower pain scores after 2 days compared to a control group (4.57 ± 0.60 vs. 5.71 ± 0.45). Sodium hypochlorite is excellent for root canal disinfection, as irrigating with 1% NaOCl completely eliminated the bacteria from canals in 65% patients. A 0.05% CPC mouthwash proved effective for perioperative patient care, significantly decreasing gingival bleeding (p < 0.001) and suppressing Streptococcus levels even one week post-surgery. Lastly, a 6% H2O2 paint-on varnish and 6% H2O2 tray formulations successfully bleached the teeth of 40 patients, maintaining a noticeably whiter appearance up to the 6-month follow-up, with significant color differences from the baseline (p < 0.005). Synthetic compounds have a large research base, which also provides a greater awareness of their mechanism of action and potential adverse effects. For a better understanding of how they work, several methods and assays are performed. These are protocolary techniques through which a compound's efficacy and toxicity are established.

Hypersensitivity reaction of the gingiva to chlorhexidine: case report and literature review

OBJECTIVE

The aim of this case report was to document a case of delayed-type hypersensitivity reaction of the gingiva to chlorhexidine and review the literature on oral mucosal hypersensitivity reactions associated to chlorhexidine-containing oral hygiene products.

STUDY DESIGN

A 58-year-old man presented with a well-demarcated erythematous area on the right upper anterior gingiva. Incisional biopsy was performed. Postoperatively, chlorhexidine digluconate gel was prescribed twice a day, but the patient did not use it because he experienced intense burning immediately after the first application. The microscopic diagnosis was nonspecific mucositis. Hypersensitivity reaction was suspected. The patient reported use of 0.004% chlorhexidine digluconate-based toothpaste twice a day in the past few years. A delayed-type hypersensitivity reaction to the toothpaste was hypothesized, and its use was discontinued. Chlorhexidine, the common ingredient of both the toothpaste and the gel, was considered the allergen. The literature was reviewed on chlorhexidine-induced oral hypersensitivity reactions.

RESULTS

Two weeks after cessation of toothpaste use, complete remission of the lesion was observed without additional intervention. Four years later, no recurrence has been reported. The literature review yielded 7 studies reporting 20 patients with intraoral manifestations of hypersensitivity reactions associated with chlorhexidine-containing oral hygiene products.

CONCLUSIONS

Clinicians should be aware that oral hygiene products containing even low concentrations of chlorhexidine might induce hypersensitivity reactions.

Chlorhexidine Allergy: Current Challenges and Future Prospects

Chlorhexidine is a synthetic bisbiguanide antiseptic and was introduced in healthcare use in 1954. Allergy to chlorhexidine has been increasingly reported particularly in the perioperative and medical procedural settings. The hypersensitivity reactions range from mild cutaneous reactions to anaphylaxis or death. There are many products and medical devices containing chlorhexidine that sometimes lack standardized labeling. With the various routes of chlorhexidine exposure, accidental or recurrent reactions in chlorhexidine-allergic patients have been reported. Therefore, we aim to review the most recent evidence in clinical manifestations, diagnostic methods, management, and preventive measures with a focus on the unique features of chlorhexidine allergy.