# Rash and skin toxicity (acneiform rash, paronychia)

Source: https://onco.cc/terms/rash-skin-toxicity/  
OnCo record `rash-skin-toxicity` (Term). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Skin reactions from cancer drugs, ranging from the acne-like rash that nearly everyone on an EGFR inhibitor gets (a sign the drug is working) to painful nail-fold infections, itching, and rare severe blistering reactions.

## Summary

EGFR inhibitors (cetuximab, panitumumab, osimertinib, amivantamab) cause acneiform rash, paronychia and dry skin in most patients through on-target blockade in skin, managed with prophylactic doxycycline, topical steroids and moisturisers; the rash correlates with response. MEK and BRAF inhibitors, ADCs (enfortumab vedotin can cause severe, occasionally fatal skin reactions), immunotherapy (maculopapular rash, pruritus, vitiligo in melanoma, which predicts response), and chemotherapy (hand-foot syndrome, hyperpigmentation) all have characteristic patterns. Severe cutaneous adverse reactions (Stevens-Johnson syndrome, toxic epidermal necrolysis) are rare but require permanent discontinuation. Skin toxicity is a leading cause of dose reduction and of visible distress for patients.

## Fields

- Kind: Term
- Last checked: 2026-09-09
- Also known as: rash; skin rash; skin toxicity; skin toxicities; dermatological toxicity; dermatologic toxicity; cutaneous toxicity; acneiform rash; acneiform; papulopustular rash; EGFR rash; paronychia; nail changes; xerosis; dry skin; photosensitivity; maculopapular rash; Stevens-Johnson; SJS; vitiligo; hyperpigmentation

## Notes

- Cetuximab and panitumumab (the EGFR antibodies used for RAS wild-type metastatic disease) cause an acne-like rash on the face, neck, chest and back, most likely to start in the first 2 or 3 weeks. Macmillan says to contact the hospital as soon as possible on the 24-hour number for any skin change, because creams, steroids or antibiotics may be needed and treatment may be paused; do not use products containing alcohol or anti-acne products unless prescribed, moisturise with unperfumed moisturisers, and use sun cream of at least SPF 30 with clothing and a hat. Blood magnesium and calcium are checked regularly because these drugs lower them.

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Drug_eruption
- Wikipedia: https://en.wikipedia.org/wiki/Drug_eruption
- Macmillan: cetuximab (Erbitux): https://www.macmillan.org.uk/cancer-information-and-support/treatments-and-drugs/cetuximab
- Macmillan: panitumumab (Vectibix): https://www.macmillan.org.uk/cancer-information-and-support/treatments-and-drugs/panitumumab

## Connected records

- terms: [Dose reduction, interruption and discontinuation](https://onco.cc/terms/dose-modification/), [Hand-foot syndrome and hand-foot skin reaction](https://onco.cc/terms/hand-foot-syndrome/), [Immune-related adverse events (irAEs)](https://onco.cc/terms/irae/), [Living with FOLFOX, CAPOX, FOLFIRI and the EGFR antibodies](https://onco.cc/terms/chemotherapy-side-effects-colorectal/), [Tyrosine kinase inhibitor (TKI)](https://onco.cc/terms/tki-term/)
- cancers: [Colorectal cancer](https://onco.cc/cancers/colorectal/)
- fronts: [Supportive Care & Survivorship](https://onco.cc/fronts/supportive-care/)
- drugs: [Cetuximab](https://onco.cc/drugs/cetuximab/), [Enfortumab vedotin](https://onco.cc/drugs/enfortumab-vedotin/), [Osimertinib](https://onco.cc/drugs/osimertinib/)

---
JSON: https://onco.cc/api/v1/entities/rash-skin-toxicity.json