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IV. Exudative urticaria: associated with serum oozing and matting of the
hair and hair loss.
V. Gyrate urticaria: bizarre serpiginous and arciform shapes and often
associated with drug reactions.
Differential diagnoses:
- folliculitides
- vasculitis
- erythema multiforme
- cutaneous infiltrates (amyloidosis, neoplasia)
-
Diagnosis:
History
- record of client observations (seasonality, drug exposure, feeds, housing,
environment, association with exercise)
- Duration of the lesions
- Location of the lesions (contact sites?)
- Grooming protocol
- Parasite control
A thorough history should allow you to rule in/out drugs, parasitism, infections and
give clues as to the likelihood of physical urticaria.
Diagnostic tests
Treatment:
- Permanent marking pen to assess persistence of individual lesions
- Histopathology for lesions that persist greater than 24 hours (infiltrative
urticaria, vasculitis)
- Assess for dermatographism (blunt pressure applied and observe for
wheal formation)
- Local application of heat (water > 44 o C) or cold (ice cube)
- Exercise challenge
- IDT (intradermal skin testing for airborne allergens)
- Hymenoptera testing
- Novel protein hypoallergenic diet 6 to 8 weeks
- Avoidance of triggers if identified
- Trigger “desensitisation”
ACVSC Proceedings Dermatology Chapter Science Week 2005