Chronic Skin Side Effects May Persist After Immunotherapy

Immunotherapies have revolutionized cancer treatment and offered hope to many patients, while treatment-related adverse effects are attracting increasing attention. Immune checkpoint inhibitor immunotherapies activate the immune system against cancer cells. However, this process can target healthy tissues as well as cancer cells, causing immune-related adverse events (irAEs).

Immunotherapy and Skin Side Effects

The skin is among the organs most often affected by immunotherapy. Reactions such as itching, redness, rashes, and dermatitis can substantially impair quality of life. More importantly, in some patients these problems persist for months or even years after treatment stops. How long do chronic skin effects last? Who is at greatest risk, and how should they be managed?

A new Vanderbilt University study, published on 12 March 2025 in JAMA Dermatology, examines the prevalence and duration of chronic immunotherapy-related skin reactions and their effects on patients in detail. It suggests these effects may last longer than expected and that patients need long-term dermatological follow-up.

Details of the New Study

The study examined 318 patients treated with immunotherapy between 2015-2022 .

• Among them, 100 developed immunotherapy-related skin adverse effects .
• In 24 patients (24%), these reactions became chronic, persisting for at least 3 months after treatment stopped.
• A detailed analysis of patients followed for chronic skin reactions included 52 patients (20 women; median age 66.5 years) .

Treatment Duration and Follow-up

• Patients received nivolumab, pembrolizumab, or ipilimumab treatment.
• Median immunotherapy duration: 342 days
• Median follow-up after treatment stopped: 1032 days
• Median duration of chronic skin reactions: 629 days
• Median persistence of adverse effects after treatment stopped: 446 days

Study Findings: How Long Do Chronic Skin Effects Last?

• Chronic skin reactions developed in 24 of 100 patients (24%), or 8% of all 318 patients.
• Among the 52 patients followed, symptoms improved or resolved over time in 79% (41 patients).
• However, 41 patients (79%) still had reactions, even if mild, at month 12.
• At month 18, 28 patients (54%) still had symptoms.

These data show that symptoms improved over time in most patients, but skin reactions persisted for a long time in some .

Severity and Management

• Among the 52 patients, 85% experienced mild (grade 1 or 2) skin reactions.
• 14% developed more severe (grade 3) reactions.
• The most common skin reactions:
  • Itching (pruritus)
  • Redness and rash (morbilliform eruption)
  • Dermatitis

The Importance of Follow-up

• Patients receiving dermatological follow-up (27 people):
  • Rate of severe grade 3 adverse effects: 46%
  • Use of biological agents: 33%
• Patients without follow-up (25 people):
  • Rate of grade 3 adverse effects: 14%
  • Use of biological agents: 0%

These findings emphasize the importance of regular dermatologist follow-up for patients developing skin adverse effects . Patients with more severe reactions were more likely to receive biological agents.

Study Limitations

• More severe cases may have been referred to dermatologists. More research is therefore needed into the long-term course of mild cases.
• Patients without follow-up may have different clinical courses. Not everyone with skin adverse effects should therefore be expected to follow the same course.

Conclusion: Skin Reactions After Immunotherapy Should Not Be Underestimated

This study shows that skin reactions after immunotherapy may persist longer than expected and require long-term follow-up .

Monitoring symptoms lasting more than 1 year is particularly important for choosing appropriate treatment plans.

Patients with skin adverse effects should not neglect regular dermatological assessments, which are important for preserving quality of life during treatment.