Use of the Rash Appearance to Distinguish Cholinergic Urticaria Subtypes: A Retrospective Cohort Study

Area of Science:

• Dermatology
• Immunology
• Allergy

Background:

• Cholinergic urticaria (CholU) is a hives condition triggered by heat, exercise, or stress.
• Classifying CholU by rash type is crucial for management, but understudied.
• This study explores rash morphology in CholU and its clinical associations.

Purpose of the Study:

• To investigate associations between CholU rash types and clinical phenotypes.
• To explore potential underlying mechanisms for different rash types in CholU.

Main Methods:

• Retrospective analysis of 64 CholU patients.
• Classification into red wheal/erythema (n=44) or goosebumps (n=20) groups.
• Evaluation of autologous sweat/serum skin tests, atopic dermatitis, and hypohidrosis.

Main Results:

• Goosebumps group: higher male proportion, hypohidrosis, and pain.
• Red wheal/erythema group: higher ASwST positivity, atopic dermatitis, and pruritus.
• Male sex significantly associated with goosebumps rash; hypohidrosis and pain also linked.

Conclusions:

• CholU patients exhibit diverse rashes, including goosebump-like eruptions.
• Goosebump-like rashes are associated with hypohidrosis and male sex.
• Rash type can aid in differentiating CholU clinical subtypes for targeted management.