Acneiform (papulopustular) rash is the most common skin side effect of EGFR inhibitors such as cetuximab, panitumumab, osimertinib, erlotinib, and afatinib, and of some MEK inhibitors. It affects 60 to 90 percent of patients on these drugs, appearing within the first two to four weeks as red bumps and pustules on the face, scalp, chest, and back. It looks like acne but is not acne, and acne treatments can make it worse. Untreated, it is one of the leading reasons patients reduce or stop an effective cancer therapy.

What causes the rash?

EGFR is essential for normal skin cell growth. Blocking it disrupts the skin barrier and provokes inflammation around hair follicles. The rash is dose-related and, in several studies, patients who develop it tend to respond better to the cancer drug, which is one more reason to treat the skin rather than stop the therapy.

What are the symptoms?

Tender or itchy red bumps and pus-filled spots on the face, scalp, upper chest, and back, followed over weeks by dryness, cracking of the fingertips, painful inflammation around the nails, and changes in eyelashes and hair. Severity is graded to guide treatment.

How is the rash treated?

Prevention works: starting an oral tetracycline antibiotic (doxycycline or minocycline), a topical steroid, moisturizer, and sunscreen at the same time as the cancer drug cuts moderate-to-severe rash by more than half in clinical trials. Established rash is treated with the same regimen at higher intensity, and severe cases with short steroid courses or isotretinoin at low dose, in coordination with oncology. Dose reduction is rarely needed when the skin is managed.

How Tono treats acneiform rash

Tono's board-certified dermatologists see patients with an EGFR inhibitor rash within days, not months, by video visit in 33 states and in person at Tono clinical centers. This is the core of supportive oncodermatology at Tono. We start preventive regimens with the first dose, see flares within days, and manage the rash so your oncologist can keep you at full dose. Your visit ends with a written plan, prescriptions sent to your pharmacy, and follow-up scheduled with the same dermatologist. Most insurance is accepted and no referral is required.

When should I see a dermatologist for an EGFR inhibitor rash?

Ask for a dermatology plan before or at the start of an EGFR or MEK inhibitor, and see a dermatologist promptly if a rash appears, becomes painful, or is affecting your willingness to continue treatment.