EGFR inhibitors (gefitinib, erlotinib, afatinib, osimertinib, etc.) — almost all patients develop cutaneous reactions because the EGFR receptor is also expressed on skin follicles and epidermal cells.Rash intensity correlates positively with tumor response — this is often a good prognostic sign, but proper dermatologic management is essential to avoid forced dose reduction or discontinuation.
TKI Targeted Therapy — Cutaneous Toxicity Management
Tyrosine kinase inhibitors (TKIs) and other targeted cancer therapies have transformed oncology but produce a unique spectrum of cutaneous toxicities. This article summarizes recognition, prevention, and management based on Taiwan TDA / Lung Cancer Society 2024 consensus + ASCO / ESMO international guidelines.
EGFR Inhibitors — Most Common Skin Reactions
Drugs: Erlotinib (Tarceva), Gefitinib (Iressa), Afatinib (Giotrif), Osimertinib (Tagrisso), Cetuximab, Panitumumab.
Acneiform / papulopustular eruption
- Most common: 50-90% of patients
- Onset: 1-2 weeks; peak 3-4 weeks; gradual improvement after
- Distribution: face, scalp, chest, back (sebum-rich areas) — unlike acne, includes pustules WITHOUT comedones
- Severity often correlates with anti-tumor response
STEPP Prophylactic Protocol (Lacouture et al., JCO 2010)
Start day 1 of TKI, continue 6+ weeks:
- Sunscreen SPF 30+ daily
- Moisturizer BID (ceramide-based)
- Mild topical steroid (hydrocortisone 1%) BID
- Doxycycline 100 mg BID × 6 weeks (or minocycline)
STEPP reduced grade ≥ 2 dermatologic toxicity by ~50%.
Reactive Treatment (CTCAE Grading)
| Grade | Features | Treatment |
|---|---|---|
| 1 (Mild) | < 10% BSA, no symptoms | Continue TKI; topical hydrocortisone 1% + topical clindamycin 1% |
| 2 (Moderate) | 10-30% BSA, mild symptoms; impacts QoL | Continue TKI; mid-strength steroid + oral doxycycline 100 mg BID |
| 3 (Severe) | > 30% BSA or local symptoms | Hold TKI 1-2 weeks; oral steroid pulse + doxycycline + dermatology referral |
| 4 (Life-threatening) | Generalized, infectious complications | Discontinue TKI; hospitalize |
Other EGFR-Related Skin Toxicities
- Xerosis: severe dryness; daily ceramide moisturizer + bath oil
- Paronychia: periungual inflammation, pyogenic granuloma; topical / intralesional steroid + topical antibiotic; consider granuloma excision
- Hair changes: trichomegaly (long curly eyelashes), hypertrichosis, scalp scarring alopecia
- Mucositis: oral / nasal; gentle hygiene, topical steroids
VEGF / Multikinase Inhibitors
Drugs: Sorafenib, Sunitinib, Regorafenib, Lenvatinib, Pazopanib.
- Hand-foot skin reaction (HFSR): distinct from chemotherapy HFS — focal hyperkeratotic painful lesions on pressure points; 60% incidence
- Prevention: pressure padding, moisturizer with urea / lactic acid, careful manicure
- Treatment: dose reduction, topical corticosteroid, keratolytic (urea 20-40%, salicylic acid)
BRAF / MEK Inhibitors
Drugs: Dabrafenib, Vemurafenib, Trametinib, Cobimetinib.
- Photosensitivity (BRAF): sunburn-like reactions; rigorous sunscreen mandatory
- Squamoproliferative lesions (BRAF mono): keratoacanthomas, SCCs (paradoxic MAPK activation in BRAF-WT cells); resolved by adding MEK inhibitor
- Combined BRAF + MEK reduces these but adds: pyrexia, peripheral edema, retinopathy
Immune Checkpoint Inhibitors (ICI)
Drugs: Pembrolizumab, Nivolumab, Ipilimumab, Atezolizumab, Durvalumab.
- Maculopapular rash: most common irAE (immune-related adverse event); 30-50%
- Vitiligo-like depigmentation: especially in melanoma patients; correlates with anti-tumor response
- Pruritus: very common; antihistamines, mid-strength TCS, gabapentin if refractory
- Lichenoid eruption, psoriasiform, eczematous: variable
- Severe (rare but life-threatening): SJS/TEN, DRESS, BP-like bullous reaction — discontinue and dermatology / oncology consult
Summary
Cutaneous toxicities of targeted cancer therapies are often manageable with prophylactic and reactive dermatologic care, allowing oncology treatment to continue. Patient education, dermatologist co-management, and STEPP-style prophylaxis dramatically improve outcomes and adherence. Don't reflexively reduce or stop the targeted agent — discuss with both oncology and dermatology first.