Incidence of Skin Rash with Paracetamol (Dolo) 500mg
Skin rash from paracetamol (acetaminophen) is rare, occurring in well under 1% of patients, with severe cutaneous reactions being exceptionally uncommon. 1
Documented Incidence Rates
The FDA drug label for paracetamol warns that acetaminophen "may cause severe skin reactions" but does not provide a specific incidence rate, indicating these reactions are uncommon enough not to warrant precise quantification in routine use. 1 The label lists symptoms including skin reddening, blisters, and rash, with instructions to stop use immediately if a skin reaction occurs. 1
Evidence from Clinical Studies
Research data provides limited but informative incidence estimates:
Cross-reactivity studies in patients with NSAID-induced skin disorders found that approximately 19% of patients with aspirin-induced urticaria also reacted to acetaminophen, though this represents a highly selected population already predisposed to drug reactions. 2 This figure does not represent the general population risk.
Case reports document rare presentations including fixed drug eruption 3, 4 and cellulitis-like reactions 4, but these remain isolated case reports rather than systematic incidence data.
N-acetylcysteine treatment studies (the antidote for paracetamol overdose) showed 14% of Chinese patients developed skin rash, but this was attributed to the antidote itself rather than paracetamol. 5
Clinical Context and Risk Factors
The general population risk of paracetamol-induced rash is substantially lower than with other analgesics. For comparison:
- NSAIDs like amprenavir show rash incidence ≤27% 6
- Antiretroviral NNRTIs cause rash in the majority of cases 6
- Tyrosine kinase inhibitors show rash rates of 11-43% depending on the agent 6
Risk factors for acetaminophen intolerance include:
- History of aspirin-induced anaphylactoid reactions (RR = 5.7) 2
- Aspirin intolerance (RR = 5.4) 2
- Atopic status increases risk specifically for other NSAIDs but less clearly for acetaminophen 2
Severity Spectrum
When rash does occur with paracetamol:
- Most reactions are mild with simple erythema or urticaria 1
- Severe reactions are extremely rare, including Stevens-Johnson syndrome, toxic epidermal necrolysis, and bullous fixed drug eruption 3, 4
- Fixed drug eruption represents the most commonly reported pattern in case literature, recurring in the same anatomic location with re-exposure 3, 4
Critical Management Points
If skin reaction occurs:
- Stop paracetamol immediately and permanently 1
- Seek medical evaluation right away, particularly if accompanied by blistering, mucosal involvement, or systemic symptoms 1
- Do not rechallenge with paracetamol if confirmed as causative agent 7
Common pitfall: Cellulitis-like presentations may be misdiagnosed as infection rather than drug reaction, leading to inappropriate antibiotic therapy and continued paracetamol exposure. 4