A six-month-old, intact female, 1.18 kg mixed-breed cat was referred because of severe pruritus and an erythematous lesion on both ear margins. The referring veterinarian prescribed systemic antibiotic treatments, including Cephalexin at a dosage of 20 mg/kg twice daily for five days, Doxycycline at 5 mg/kg twice daily for two weeks, and Metronidazole at 10 mg/kg twice daily for two weeks, along with oral prednisolone at 0.5 mg/kg twice daily for five days. However, no improvement was observed. Surgical excision of bilateral ear margins did not help with a resolution. The clinical examination revealed a papulocrustous lesion on the ear pinna and a left medial hind limb. The left popliteal lymph node was slightly enlarged. The cytological samples from the skin lesions on the ear margin and left medial hind limb confirmed a secondary bacterial infection.The cytology of the lymph node revealed neutrophilic lymphadenitis. A skin biopsy was performed on both the right ear margin and the left medial hind limb under sedation. The histopathological examination showed moderate perivascular diffuse infiltrate of well-differentiated, non-malignant featured mast cells with neutrophils and eosinophils in the dermis. A definitive diagnosis of urticaria pigmentosa was made based on the clinical signs and histopathological results. The cat was administrated cetirizine (1.7 mg/kg) once daily. Evident improvement was noted after two weeks of treatment. The same treatment was continued for seven days, resulting in complete remission. No relapse occurred after the medication was withdrawn.

A two-year-old, spayed female, 22.5 kg Pungsan was referred with chronic crusts and erosion on the nose. A referring veterinarian prescribed an anti-inflammatory dose (0.5-1 mg/kg/day) of oral glucocorticoids for 5 months, but skin lesions showed no meaningful improvement. A dermatological evaluation revealed a crust, depigmentation, erosion, and erythematous lesion over the nasal planum with a loss of the normal cobblestone texture. Also, firm and multifocal plaques over the thigh, groin, axilla, and dorsum were detected. A cytology examination on the nose, thigh, groin, axilla, and dorsum revealed moderate neutrophilic inflammation and bacterial infection. Abdominal radiography and ultrasonography revealed subcutaneous calcified materials along the thigh, groin, axilla, and dorsum. Calcinosis cutis was suspected because of the adverse effect of previous prolonged corticosteroid therapy. A histopathology examination of the nose lesion revealed moderate to severe degenerative or apoptotic changes of the basal layer and lymphoplasmacytic interface dermatitis. Facial discoid lupus erythematosus (FDLE) was diagnosed based on the history and the clinical, cytological, and histopathological results. Minocycline (7 mg/kg PO q 12 h) and niacinamide (500 mg/dog PO q 12 h) were prescribed as initial treatment.Glucocorticoids were not administered due to the presence of calcinosis cutis induced by previous corticosteroid treatment. After 6 weeks of treatment, the clinical signs on the nose were mildly improved. At this time, topical 1% pimecrolimus cream (twice daily) was initiated, while minocycline and niacinamide were continued at the same dose. The nasal planum markedly improved after 6 weeks of additional treatment, hence minocycline and niacinamide were prescribed for an additional 2 weeks and stopped, and the patient was continued solely on topical pimecrolimus. The dog’s skin lesion has been maintained in clinical remission with topical 1% pimecrolimus twice daily for more than 5 months.