Blisters may be widespread or localized. Oral manifestations may be erythematous,
vesicular, erosive, or ulcerative and can involve the tongue, as well as the buccal mucosa
or gums. Blistering eruptions, such as TEN or SJS, may cause severe oral ulceration.
Any persistent oral ulcer should be biopsied to exclude malignancy.
1. Fixed drug eruption
• One or more well-defined circular, erythematous plaques that usually blister and then
resolve over 7–10 days, leaving a hyperpigmented macule. Itching is uncommon.
• Causes: tetracycline, sulfonamides, allopurinol, aspirin (analgesic is taken for menstrual
pain or headaches), phenolphthalein. Also consider herbal medicines and other over-the-
counter preparations that are ingested sporadically.
2. Aphthous ulcers
• Aphthous ulcers are caused by drugs such as azathioprine, captopril, ciclosporin,
fluoxetine, sertraline, and sulfonamides.
• NSAIDs and nicorandil cause oral ulcers that may simulate giant aphthae, but the ulcers
do not have the erythematous halo or yellow base of an aphthous ulcer.
3. Erythema multiforme
• EM is an acute, self-limited illness. Infection (most often herpes simplex) is a much
more likely trigger than a drug.
4. Stevens–Johnson syndrome and toxic epidermal necrolysis
Life-threatening cutaneous reactions, with overlapping features, caused by drugs such as
sulfonamides, aminopenicillins, anti-epileptics, barbiturates, NSAIDs, and allopurinol.
Patients may have underlying diseases, particularly AIDS. Course protracted—at least 3
weeks.
5. Coma-induced blisters
• Seen in association with decreased level of consciousness caused by overdose of agents
such as barbiturates, benzodiazepines, heroin, methadone, imipramine, and alcohol. (Also
reported in some neurological and metabolic causes of reduced levels of consciousness.)
6. Chemotherapy agents
• Mucosal ulcers are common.
7. Contact stomatitis
• The patient may notice an oral burning sensation and xerostomia.
• Reactions develop after days or years of exposure.
• Patch testing will confirm the diagnosis.
• Caused by agents such as topical anaesthetics and antiseptic mouthwashes.
8. Cutaneous ulcers
• Nicorandil causes large, deep, painful persistent ulcers on perianal skin and other sites.
ulcers may resemble pyoderma gangrenosum (PG) or a cutaneous malignancy.
• Cocaine abuse may cause PG.
