Recurrent aphthous stomatitis

Behcet disease is a variable-vessel vasculitis, the only vasculitis that can involve arteries and veins of any size, marked by recurrent oral and genital ulceration, uveitis, skin lesions, and pathergy. There is no confirmatory laboratory test; diagnosis is clinical. Treatment is organized by organ severity, from colchicine for mucocutaneous disease to urgent immunosuppression and tumor necrosis factor inhibitors for sight-, organ-, or life-threatening involvement.

Celiac disease is an immune-mediated small-intestinal enteropathy triggered by dietary gluten in genetically predisposed individuals, presenting with malabsorptive diarrhea, iron-deficiency anemia, or dermatitis herpetiformis. Diagnosis requires IgA tissue transglutaminase serology with a total IgA level while the patient still eats gluten, confirmed by duodenal biopsy showing villous atrophy, and the only treatment is a strict lifelong gluten-free diet.

Crohn disease is a chronic transmural inflammatory bowel disease that can affect any segment from mouth to anus in skip lesions, most classically the terminal ileum, and is confirmed by ileocolonoscopy showing cobblestoning, skip areas, and non-caseating granulomas on biopsy. Management follows an ordered sequence of glucocorticoid or budesonide induction followed by immunomodulator or biologic maintenance, with surgery reserved for fixed complications rather than cure.

Systemic lupus erythematosus is a chronic multisystem autoimmune disease in which antinuclear and other autoantibodies drive immune-complex deposition and organ injury across skin, joints, kidneys, blood, serosa, and the nervous system. Diagnosis rests on a positive antinuclear antibody plus weighted 2019 EULAR/ACR criteria totaling 10 or more points. Hydroxychloroquine is lifelong first-line therapy for nearly every patient, with glucocorticoids and steroid-sparing immunosuppression added for moderate to severe or organ-threatening disease.

Acute HIV infection, also called the acute retroviral syndrome, is the symptomatic viremic phase in the days to weeks after HIV acquisition, presenting with fever, fatigue, myalgia, rash, and pharyngitis at a time when antibody testing may still be negative. Diagnosis requires an HIV RNA viral load, and antiretroviral therapy should begin as soon as the patient is ready, regardless of CD4 count.

Herpes simplex virus type 1 or 2 establishes lifelong latency in sensory ganglia after mucocutaneous infection, causing painful vesicular-to-ulcerative outbreaks of the mouth or genitals with intermittent asymptomatic shedding; diagnosis is by NAAT of an ulcer swab and treatment is oral nucleoside analogues, escalating to intravenous acyclovir for encephalitis, severe mucocutaneous disease, or disseminated infection in immunosuppressed hosts.

Squamous cell carcinoma of the oral cavity and oropharynx arises along two distinct etiologic pathways, tobacco/alcohol-driven disease in older adults and HPV-driven oropharyngeal disease with a better prognosis, and is diagnosed by biopsy with p16 testing and staged before a surgery-or-chemoradiation decision.

Neutropenia is a reduced absolute neutrophil count that raises infection risk sharply once the count falls below 500/microL, most often from chemotherapy or another marrow-suppressing or idiosyncratic drug. Diagnosis rests on a repeat CBC with differential and smear review followed by a directed search for cause, and management centers on stopping the offending agent, treating any underlying disease, and using G-CSF and neutropenic precautions when the count is low or the patient is febrile.