How immunotherapy affects your skin

Dr Daleen Geldenhuys explains how immunotherapy affects the skin, specifically immune checkpoint inhibitors.

There are different types of immunotherapies but the side effects that    are discussed below focus on therapies that activate T-lymphocytes. These specific immune therapies are immune checkpoint inhibitors (ICIs).

ICIs enhance the host anti-tumour response. The main target is the cancer cell, but sometimes the activated T-cells may attack innocent cells. This is called immune-related adverse events. These are graded the same as other therapy-induced side effects: Grade 1 to 4; where 1 is a mild inconvenience, but 4 may be life-threatening. 

Grades 1 to 2 will be managed to ensure the ongoing benefit of immunotherapy, but therapy is usually permanently withdrawn if the reaction is too severe. Fortunately, most skin adverse effects are mild and can be managed without compromising the treatment.

Factors that may increase side effects

There are considerations when immunotherapy is prescribed and if you’ve a history of pre-existing skin diseases, such as allergic skin diseases, psoriasis, or vitiligo. These conditions may flare with ICIs.

Previous skin reactions to medication may predispose you to a higher risk of skin side effects.

Different immunotherapeutic agents have a decreased risk of developing skin side effects than other agents. 

It appears that patients with advanced disease and higher tumour burden may have a lower risk of developing skin side effects.

Side effects: how to treat them?

Pruritus (itchy skin) is quite common. Oral antihistamines and topical agents, such as camomile lotion or cortisone-based cream, may be effective. There are many different over-the-counter creams, soaps, and shampoos that may assist in the treatment of mild skin irritation. Severe itching may need oral gabapentin or pregabalin. Anti-depressants may also help.

Maculopapular eruptions (elevated  reddish patches on the skin) are common skin reactions to medications. This may resolve spontaneously and therapy may be continued if it’s mild. Corticosteroid creams may be applied. If more severe, a short course of oral corticosteroids may be necessary.

Eczematous skin reactions (itching, dryness, and inflammation) are treated according to the severity of the reaction. Topical or oral corticosteroids may be used, but if large areas of the skin surface are involved, immunotherapy may need to be interrupted until the reaction has improved.

Lichenoid eruption (itchy, reddish, purple-raised skin rash) is an uncommon rash. Again, corticosteroid therapy is used. If it involves a big area of skin, a dermatologist will be consulted to advise on more extensive therapy. Occasionally, a different type of antibody, oral chemotherapy, narrowband ultraviolet B (NBUVB) phototherapy or oral retinoids can be used.

Psoriasiform eruption (thickened, reddish skin around joints). In other words, the extensor surfaces of the skin, the part of skin that stretches when you straighten your joints. Topical high-potence corticosteroid cream and NBUVB phototherapy can be used.

For more severe reactions, a dermatologist will be consulted and if severe, admission to hospital may be required to assist with therapy. The treatment hinges on the presence or absence of symptoms of concurrent inflammatory arthritis. If arthritis is present because of ICIs, treatment may be escalated and will involve other therapies.

Bullous pemphigoid (large, tense, itchy, fluid-filled blisters on the skin). High-potency corticosteroid cream for mild eruptions to oral corticosteroids if more severe. Oral antibiotics can change the gut bacteria, which may affect the response to immunotherapy.

Stevens-Johnson syndrome (severe blistering, skin death, and shedding) is a rare reaction but extremely severe. A multi-disciplinary team will be involved and you may need intensive care admission and discontinuation of therapy.

Vitiligo (smooth, milky white patches) can develop from the use of the ICIs, especially in treatment of melanoma. Sunscreens are essential but special care should be taken to avoid any attempt to reduce autoimmunity as repigmentation is associated with melanoma recurrence.

Prompt reporting

ICIs have changed the treatment landscape of cancer and have improved lives. Though, it remains a delicate balance of effectiveness, prolonged survival, quality of life, and possible life-threatening side effects. 

You must report side effects promptly. Often a simple change or addition of skincare products may make a huge difference in tolerability, without adding more medication  or stopping therapy.

Dr Daleen Geldenhuys is a specialist physician and medical oncologist who works at West Rand Oncology Centre at Flora Clinic and the ICON Unit at Johannesburg Surgical Hospital. She treats patients with all types of cancer and enjoys clinical research, and is a member of SASMO, SASTECS, ESMO and ENETS.

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