What medications can cause pityriasis rosea?

Medications That Can Cause Pityriasis Rosea

Epidermal growth factor receptor inhibitors (EGFRis), mitogen-activated protein kinase inhibitors (MEKis), and mammalian target of rapamycin (mTOR) inhibitors are the most common medications that can trigger pityriasis rosea-like eruptions. 1

Common Medication Triggers

Anticancer Agents

• EGFRis (e.g., cetuximab, panitumumab, erlotinib)
• MEKis (e.g., trametinib, cobimetinib)
• mTOR inhibitors (e.g., everolimus, temsirolimus)

These medications typically cause a papulopustular exanthema that can resemble pityriasis rosea, with follicular papules and pustules that initially develop in sebaceous gland-rich areas like the face, chest, and upper back 1.

Other Medications

• Thiol-containing drugs (such as captopril, penicillamine) 1
• Non-thiol drugs (such as certain antibiotics) 1
• Chemotherapy agents including:
  • 5-fluorouracil
  • Capecitabine
  • Doxorubicin
  • PEGylated liposomal doxorubicin
  • Docetaxel
  • Cytarabine 2

Clinical Presentation of Drug-Induced Pityriasis Rosea

Drug-induced pityriasis rosea differs from classic pityriasis rosea in several ways:

• Pruritus is more common in drug-induced cases 1
• May lack the classic herald patch seen in 80% of typical pityriasis rosea cases 3
• Often has atypical morphology (papular, purpuric, vesicular, or eczematous variants) 4
• May have unusual distribution patterns rather than following Langer's lines in a "Christmas tree" pattern 4

Diagnosis

Diagnosis of drug-induced pityriasis rosea requires:

1. Thorough medication history - Check for recent initiation of any of the above medications
2. Physical examination - Look for characteristic rash patterns
3. Consider skin biopsy - May be needed in atypical cases (required in 44.4% of atypical cases in one study) 4
4. Rule out other causes - Particularly secondary syphilis, which can mimic pityriasis rosea 5

Management

When medication-induced pityriasis rosea is suspected:

1. Consider discontinuation of the offending drug if clinically appropriate 1

2. For anticancer agents causing skin reactions:

   • Grade 1-2: Continue drug at current dose and monitor
   • Grade ≥3: Interrupt treatment until improvement to Grade 0-1 1

3. Symptomatic treatment:

   • Oral antibiotic therapy (doxycycline 100 mg twice daily, minocycline 50 mg twice daily, or oxytetracycline 500 mg twice daily) for 6 weeks 1
   • Topical low/moderate potency corticosteroids 1
   • For severe cases: Systemic corticosteroids (e.g., prednisone 0.5-1 mg/kg) 1
   • Antihistamines for pruritus 5

4. For severe or persistent cases:

   • Consider oral acyclovir (though evidence is mixed) 3, 6
   • Ultraviolet phototherapy may be beneficial but carries risk of hyperpigmentation 7

Important Considerations

• Drug-induced pityriasis rosea may follow two courses after drug withdrawal:

  • Complete recovery in approximately 50% of cases
  • Continued disease despite drug withdrawal in the other 50% 1

• Recovery following drug withdrawal is more likely in thiol-triggered cases 1

• Patients who do not improve after drug withdrawal should be managed similarly to idiopathic pityriasis rosea 1

• Monitor pregnant women closely as pityriasis rosea during pregnancy has been linked to spontaneous abortions 5

By identifying the causative medication and implementing appropriate management strategies, most cases of drug-induced pityriasis rosea can be effectively controlled with minimal impact on patient morbidity and mortality.