Disease or condition Clinical characteristics
Recurrent aphthous stomatitis Appearance of ulcers (aphthae) in oral mucosa with yellowish base, surrounded by an erythematous halo and regular margins and that disappear without treatment. Acute course
Behçet’s disease Appearance of aphthae in the oral mucosa with genital and ocular ulcers
Eerythema multiforme Target-shaped skin lesions, oral erosions, involvement of lips in the form of erosions and crusts
Erosive lichen planus Appearance of Wickham striae and erosive lesions
Oral candidiasis Whitish lesions that detach on scraping and atrophic erythematous areas
Acute herpetic gingivostomatitis Prodromic symptoms followed by the onset of small yellowish vesicles that rapidly rupture, giving rise to ulcers with an erythematous halo. It affects free and attached g ingiva.
Impetigo Bacterial infection with appearance of skin ulcers covered by a honey-colored crust. It affects face, arms and legs. It is more frequent in children.
Disease by linear IgA deposit Symmetric blisters and pruritic lesions, target-shaped lesions
Mucosal pemphigoid or cicatricial pemphigoid Possible  manifestation of an underlying malignant disease: oral lesions do not precede skin lesions, and blisters are smaller with a shorter duration than in PV. They heal rapidly without scarring
Bullous pemphigus Vesicles or tension blisters with clear content that develop on normal or erythematous skin; intense pruritus, symmetric lesions that appear on flexion areas, root of extremities, thighs, and abdomen; rare on mucosae.
Herpetiform dermatitis 1-3 cm erythemas that infiltrate palate and buccal mucosa; aphthae on labial mucosa. They appear months or years after the appearance of lesions on skin
Epidermolysis bullosa Development of blisters with minimal pressure, ring-shaped atrophic scars on the inner surface of limbs and articulations
Paraneoplastic pemphigus Autoimmune syndrome associated with lymphoproliferative neoplasm of B cells
Erythematous pemphigus There are usually no oral lesions
Pemphigus foliaceus There are usually no oral lesions
Chronic benign pemphigus familiaris There are usually no oral lesions
Disseminated lupus erythematosus Systemic signs (fever, asthenia) normally accompanied by petechiae, edemas and dry mouth
Crohn’s disease and hemorrhagic rectal colitis Mucocutaneous signs accompanied by abdominal pain, aphthae in oral mucosa, asthenia, weight loss, and anorexia
Folic acid or vitamin B12 deficiency Oral pain, erythematous tongue, asthenia and anemia, paresthesias in limbs, and physical problems
Hypochromic iron deficiency Pallor, fatigue, cephalalgias, vertigo, buzzing in the ears, irritability, insomnia, concentration problems, sensitivity to cold, anorexia and nausea
Enteropathic acrodermatitis Loss of taste and smell, sight problems, intense diarrhea, alopecia, and hypertension
Table 1: Differential diagnosis of oral lesions in pemphigus vulgaris.