What is the best course of treatment for a 47-year-old female with a history of Polymorphic Light Eruption (PMLE) and recent chemotherapy treatment, presenting with flushing to arms and face, rash to cheeks and chin, and occasional breakouts to forehead, exacerbated by heat?

Treatment of Post-Chemotherapy Facial Flushing and Rash with History of PMLE

This patient requires a multi-pronged approach targeting post-chemotherapy inflammatory skin changes: initiate oral doxycycline 100 mg twice daily for at least 6 weeks combined with low-potency topical corticosteroids (hydrocortisone 2.5% or alclometasone 0.05% twice daily) to the affected facial areas, along with strict behavioral modifications including avoidance of hot water exposure and heat triggers. 1

Clinical Context and Diagnosis

This presentation suggests chemotherapy-induced papulopustular eruption (acneiform rash) overlapping with heat-exacerbated flushing, rather than active PMLE, given:

• The temporal relationship to chemotherapy (one year post-treatment with persistent changes) 1
• Distribution pattern (face, cheeks, chin, forehead) matching typical chemotherapy-related dermatological toxicity 1
• Heat exacerbation and flushing components suggesting inflammatory barrier dysfunction 1
• The history of PMLE is relevant for photoprotection but likely not the primary driver of current symptoms 2, 3

Primary Treatment Strategy

Pharmacological Management

Oral tetracycline antibiotics are the cornerstone of therapy due to their anti-inflammatory and antimicrobial properties:

• Doxycycline 100 mg twice daily OR minocycline 100 mg once daily for minimum 6 weeks 1
• Alternative antibiotics if intolerant: cephalexin 500 mg twice daily or trimethoprim-sulfamethoxazole 160/800 mg twice daily 1
• These agents target the inflammatory infiltrate and reduce susceptibility to secondary bacterial infection common in chemotherapy-induced skin changes 1

Topical corticosteroids should be applied concurrently:

• Low-potency agents preferred for facial application: hydrocortisone 2.5% or alclometasone 0.05% twice daily 1
• Can escalate potency if grade 1-2 severity persists after 2 weeks 1
• The benefit of prophylactic topical steroids remains somewhat controversial, but therapeutic use is well-established 1

Behavioral and Skin Care Modifications

Critical avoidance measures to prevent exacerbation:

• Avoid frequent washing with hot water (showers, baths, hand washing) - this is particularly important given heat exacerbation 1
• Avoid skin irritants including over-the-counter anti-acne medications, solvents, and disinfectants 1
• Avoid excessive sun exposure given PMLE history 1

Essential skin care regimen:

• Alcohol-free moisturizers at least twice daily, preferably urea-containing (5-10%) formulations 1
• Broad-spectrum sunscreen (SPF 15 minimum, UVA/UVB protection) applied to exposed areas every 2 hours when outside 1
• This addresses the impaired skin barrier function common after chemotherapy 1

Escalation Strategy if Initial Treatment Fails

If no improvement after 2 weeks or worsening despite adherence:

Consider short-course systemic corticosteroids:

• Prednisone 0.5-1 mg/kg body weight for 7 days with weaning over 4-6 weeks 1
• This approach is supported for grade 3 severity, though evidence is from uncontrolled studies 1
• Given the patient's history of acute flares with PMLE, a short course of prednisolone has demonstrated efficacy (mean 2.8 days for itch resolution, 4.2 days for rash clearance) 4

Rule out secondary infection if:

• Painful skin lesions develop 1
• Yellow crusts or discharge appear 1
• Pustules extend to arms, legs, or trunk 1
• Failure to respond to oral antibiotics 1
• Obtain bacterial culture and adjust antibiotics based on sensitivities for at least 14 days 1

Special Considerations for PMLE History

While the current presentation appears primarily chemotherapy-related, the PMLE history warrants:

• Continued photoprotection as outlined above 1, 2
• Recognition that PMLE typically presents as pruritic papules/vesicles/plaques developing hours to days after UV exposure 2, 3
• If true PMLE flares occur concurrently, topical corticosteroids remain first-line with potential for short-course oral prednisolone 4, 5
• Photohardening therapy (PUVA or narrow-band UVB) is typically reserved for recurrent PMLE but is NOT appropriate during active inflammatory chemotherapy-related skin changes 1, 2, 5

Refractory Disease Options

For persistent symptoms despite 6 weeks of standard therapy:

• Oral retinoids (isotretinoin 20-30 mg/day) may be considered, though evidence is limited (Level IV) 1
• Emerging evidence suggests tofacitinib (JAK inhibitor) may benefit refractory cases by targeting the inflammatory cytokine milieu, with clinical resolution in mean 2.6 weeks 6
• These options require specialist dermatology consultation 1

Critical Pitfalls to Avoid

• Do not use aggressive anti-acne treatments - chemotherapy-induced rash is inflammatory, not comedonal acne 1
• Do not overlook infection - chemotherapy impairs antimicrobial peptide expression, increasing infection susceptibility 1
• Do not assume all facial rash is PMLE - the post-chemotherapy timing and heat exacerbation point to drug-induced toxicity as the primary driver 1
• Reassess at 2 weeks - failure to improve warrants escalation or infection workup 1