Best Practices in Allergy and Dermatology for Collaborative Diagnosis and Care


Allergists and immunologists are key collaborators of dermatologists. Conditions such as urticaria and angioedema are well suited to the expertise of an allergist. Providing dermatology referrals for patients with suspected malignancies helps get those patients to the right doctor quickly.

At a session of the 2021 American College of Asthma, Allergy & Immunology (ACAAI) Annual Scientific Meeting, held November 4-8 in New Orleans, Louisiana,1 David R. Weldon, MD, FACAAI, FAAAI, associate professor of internal medicine at Texas A&M University Health Science Center, School of Medicine at Bryan-College Station, Texas, demonstrated punch biopsies for allergists and a discussed both the scope and limitations for allergists as dermatological collaborators and diagnosticians.

Punch biopsies are a staple tool in any dermatological practice. Allergists, Weldon said, likely learned how to perform the procedure in medical school, but they are unlikely to perform it frequently in their practice. Hands-on practice equips this group with the skills to work more effectively with dermatologists to define skin conditions commonly seen in the practices of both specialties and provide tools to diagnose or refer where appropriate.

Weldon said Dermatology Time® that both specialties must take into account an individual patient’s treatment journey, not just their condition, before determining when to treat, when to refer and when to collaborate. “Even with 4 dermatologists in our area, they are still very busy and are ready to refer patients with urticaria and angioedema to me,” he said.

However, even with typical allergic conditions, dermatologists should not be surprised to see some patients referred to their practices for long-term management if they receive an unexpected diagnosis. “If I have a patient who has an initial urticarial presentation of bullous pemphigoid (PA) and the evaluation reveals BP, then that patient is immediately referred to our dermatologist for management,” said Weldon. “I can help the patient with temporization therapy, but the actual management is relegated to the dermatologist.”

For certain conditions, allergists and dermatologists must closely inspect a patient to determine the best specialist for their case. For example, in patients with atopic dermatitis (AD), dermatologists refer patients requiring biologics for the management of moderate to severe disease to Weldon, but if he has a patient who is a good candidate for a UVB therapy for the same condition, he refers to a dermatologist. “There seem to be new developments between specialties almost every year and the collaboration between allergists and dermatologists has been very educational and exciting to see the latest advancements in the manipulation of immune pathways to treat rashes in our patients,” said Weldon.

Investigative biologics ligelizumab (QGE031; Novartis International AG) for chronic spontaneous urticaria and nemolizumab (Galderma) for pruritus are two treatments that Weldon is most eager to add to its arsenal. He is also interested in new products that tackle the nonhistaminergic causes of pruritus.

While the rise of biologics has widened the overlap between the 2 specialties, he reiterated that allergists are not dermatologists and that there are some cases where referral is the first and only option. “The purpose of the workshop is not to deal with anything that might be suspected of cancer, whether it is melanoma, basal cell or squamous cell. [carcinomas]… An allergist shouldn’t be trying to manage skin cancer, in my opinion, ”said Weldon.

“One of the reasons the FDA issued a black box warning for calcineurin inhibitors for the management of [AD] was the number of reported skin cancer cases that were incorrectly diagnosed by the provider as eczema [and failed to respond with the calcineurin inhibitor]Also, he said, allergists are not trained in shave biopsies, which could lead to a misdiagnosis of a malignancy if not done correctly.

Mycosis fungoides is the exception to Weldon’s rule. “Have an allergist consider this condition as a possibility [early] can improve patient outcomes when the proper treatment is followed by a dermatologist or dermatologist in a large medical center, ”he said.

Collaboration with pathologists and dermatopathologists can help clarify what technology exists to determine T cell clonal relationships in the definition of mycosis fungoides.

Weldon noted that patients can often walk into allergy and immunology practices with rashes for which they could not be diagnosed. The biopsy capability allows them to come out knowing that an important step in the diagnostic process has been completed.


Weldon did not report any relevant disclosures.


1. Weldon DR. Practical Workshop: Overcoming Dermatitis Dilemmas: An Overview of the Biopsy. Presented at the ACAAI 2021 Annual Scientific Meeting; from November 4 to 8, 2021; in New Orleans, LA, and virtual.

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