ABSTRACT

Popa DA, Winn AR, Masters TC, Logue C. Cold Urticaria Preventing Clearance For Scientific Diving. Undersea Hyperb Med. 2025 Fourth Quarter; 52(4):621-625.

Case Description: We present a case of a 39-year-old healthy female scientific diver who developed cold urticaria (CU) 8 months prior, when immediately postpartum. She had extensive diving experience but discontinued diving during pregnancy and sought to resume diving. Before our consultation, she had seen a dermatologist and allergist for evaluation for an underlying etiology and management.

Intervention: Initial management included diphenhydramine and cetirizine with topical triamcinolone based on dermatology recommendations. Her allergist later advised discontinuing diphenhydramine and remaining on cetirizine 10mg up to four times daily, given breastfeeding concerns. Epinephrine was prescribed in case of anaphylaxis.

Outcome: The workup revealed no underlying pathology, and she was not cleared for diving until her CU was resolved. Despite antihistamines, she continues to be symptomatic, including in pools heated to 900F. Although drysuit certified, we could not clear her for scientific diving and advised against recreational diving given the risk of anaphylaxis.

Discussion: CU is an uncommon but under-reported and under-recognized condition with potentially fatal consequences for swimmers and divers. Although symptom management focuses on antihistamines, corticosteroids and omalizumab (Xolair®) may prove helpful. Nonetheless, the risk of anaphylaxis
remains, so CU should be a disqualifying condition for divers. Associated and causative conditions
require specialist evaluation, with many patients reporting spontaneous resolution within several years. Hyperbaric physicians should be aware of CU as a disqualifying condition and an etiology of a post-diving rash that could be mistaken for skin manifestations of decompression sickness.

Keywords: cold urticaria; fitness to dive; rash; scientific diving