Treating Patients With Itch

At the APP Institute Dermatology 2024, Matthew Zirwas, MD, a dermatologist at DOCS Dermatology, and Douglas DiRuggiero, DMSc, MHS, PA-C, a physician assistant at the Skin Cancer and Cosmetic Dermatology Center, tackled the diagnosis and management of patients presenting with itch.

Dr DiRuggiero started by stating that clinicians who see a patient with itch need to “put on their thinking caps” and Dr Zirwas shared that “itch is so much easier to treat now than it was 20 years ago.” They focused their session on selecting the appropriate therapy for patients with or without a rash and incorporating itch assessment into therapy selection for patients with atopic dermatitis.

After a primer on the pathophysiology of itch, they delved into how to ask patients about itch. Dr Zirwas indicated that he does not ask patients to rate their itch using a numerical rating scale of 0 being no itch and 10 being the worst itch imaginable because 1 number answering the question of “what’s your itch today?” is not particularly helpful. He suggested asking functional questions about symptoms instead. Using that information, practical types of itch can be sussed out, such as an itchy patient with an obvious diagnosis, a patient with a non-specific rash, or a patient with widespread or localized itch with no primary rash.

For an itchy patient with a non-specific rash whose biopsy shows anything other than spongiotic dermatitis, clinicians should keep biopsying and thinking. If the biopsy shows spongiotic dermatitis, the diagnosis may be atopic dermatitis, contact dermatitis, neuropathic itch, or scabies. However, the final diagnosis may only be determined based on therapeutic trials. Dr Zirwas warned that a drug reaction is an extremely rare cause of non-specific spongiotic dermatitis and should be suspected only if the biopsy shows some interface change and there is timing that makes sense.

Neuropathic itch goes to the top of the list of possible diagnoses for a patient presenting with widespread itch with little to no rash. Labs to consider if the physical examination is not diagnostic include complete blood cell count, complete metabolic panel, IgE, gliadin, HIV/hepatitis B/C, and stool studies if the patient has traveled or has gastrointestinal symptoms. If cancer is suspected, age-appropriate malignancy screening, a chest X-ray, and a lymph node examination can be done. However, Dr Zirwas cautioned to not “go fishing.” “People with new onset itch do not need full body CT scans,” he said. For the treatment of widespread itch without rash, topicals and systemics are difficult. Dr Zirwas has found success with mirtazapine, trazadone, or the nasal spray butorphanol. However, he emphasized being mindful that butorphanol is a controlled substance.

For localized itch with little to no rash, there may be issues with the small cutaneous nerve endings, brachioradial pruritus, lichen amyloidosis, scalp itch, or anogenital itch. It is reasonable to use systemics for all these conditions if localized approaches, such as over-the-counter strontium-based products, do not work.  

Dr DiRuggerio followed up with several atopic dermatitis case studies, including infantile atopic dermatitis and possible presentations of atopic dermatitis in older children, young adolescents, and young adults. He then turned his attention to a 60-year-old patient whose eczema was getting worse over the course of 2 years. There is an increase in prevalence of atopic dermatitis at ages 55 to 60. However, persistent chronic pruritus in older patients may need a thorough workup. He concluded with the following advice: “When you have eliminated everything and a lot of stuff is not working, you can begin to think out of the box.”

For more meeting coverage, visit the APP Institute Dermatology 2024 newsroom.

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Reference
Zirwas M, DiRuggiero D. Roads to treat the itchy patient. Presented at: APP Institute Dermatology; Aug 16–17, 2024; Virtual.