Case summary: A 5-year-old, spayed female, indoor-only domestic shorthair cat was referred with an acute history of multifocal cutaneous and mucocutaneous erosive-ulcerative lesions and skin detachment. The lesions occurred on the seventh day of therapy with cefadroxil. Erosive-ulcerative and occasionally crusted lesions were apparent on the medial and lateral canthus of both eyes, ventral neck, abdomen, perivulvar region, periungual skin and medial aspect of the front and hindlimbs. Diffuse and severe exfoliation was present on the dorsum and tail base and in both external ear canals. The cat was also dehydrated, tachycardic and febrile. Histopathological examination revealed extensive epidermal ulceration, interface dermatitis with vacuolar degeneration, apoptosis at multiple epidermal levels and basal, suprabasal and spinous dermoepidermal detachment. The histopathological diagnosis was consistent with Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN). The recently reported Algorithm of Drug Causality in Epidermal Necrolysis (ALDEN), currently used in human medicine, was applied and a score of +6 was calculated; this supported the view that SJS/TEN in this cat was very likely to be associated with cefadroxil administration.
Relevance and novel information: This clinical communication reports cefadroxil as a very probable cause of SJS/TEN in a cat; the ALDEN was applied in this case and supported diagnosis.