Condition	Pathogenesis	Clinical presentation and diagnosis	Treatment
Oral enanthem
Aphthous ulcers	Unknown	Shallow, round, painful ulcers, measuring up to 1 cm, with surrounding erythema and pseudomembrane¹⁴ Simple aphthae resolve in one to two weeks, not associated with skin lesions Complex aphthae tend to be larger, occur more frequently, and may indicate systemic disease (e.g., gluten sensitive enteropathy), HIV, cyclic neutropenia, systemic lupus erythematosus, inflammatory bowel disease, periodic fever, aphthous stomatitis, pharyngitis, or cervical adenitis syndrome¹⁴	Simple aphthae: supportive care Complex aphthae: treat underlying cause Pain relief: chlorhexidine (Peridex) mouthwash, lidocaine spray or ointment, anti-inflammatory or corticosteroid pastes or mouthwashes^15,16
Behçet syndrome	Unclear etiology, associations with human leukocyte antigen-B51 allele, postulated environmental triggers¹⁷	Oral aphthae, genital ulcerations, or recurrent uveitis May have arthralgia, vascular or neurologic lesions Oral lesions are painful, round, with an erythematous border, and are 1 cm to 3 cm in diameter or larger¹⁷	Corticosteroids, azathioprine (Imuran), cyclophosphamide, methotrexate, interferon alpha, ustekinumab (Stelara), infliximab (Remicade), etanercept (Enbrel), adalimumab (Humira)¹⁷
Herpangina	Coxsackievirus, echovirus¹⁸	Oral vesicles that form ulcers with associated inflammation Coxsackievirus A subtypes 1–6, 8, 10, and 22¹⁹ Thought to be on a continuum with hand-foot-and-mouth disease	Supportive care
Herpetic gingivostomatitis	Herpes simplex virus 1 and 2	Fever, anorexia, lymphadenopathy, oral erythema and small, oral vesicles on the palate, tongue, gingiva, and oral mucosa that form ulcers that may become confluent; vesicles may be present on lips; Tzanck cells may be present, diagnosis can be made by culture or immunologic assay^19,20	Supportive care; acyclovir started in the first 72 hours resulted in faster resolution of oral lesions²¹
Pemphigus vulgaris	Caused by desmosome autoantibodies²²	Oral mucosal bullae and erosions of lips, tongue, and oropharynx; may affect eyes and genital area; potentially life-threatening²² Diagnostic testing with direct immunofluorescence microscopy or serum testing	Corticosteroids, azathioprine, cyclophosphamide, intravenous immunoglobulin²²
Maculopapular or vesicular exanthem
Atopic dermatitis	Genetic, immunologic, and environmental factors²³	Erythematous plaques and vesicular lesions, excoriation, dry skin Younger children with lesions on extensor surfaces, cheeks; older children lesions on flexor surfaces; lesions on hands and feet common²⁴	Avoid triggers (e.g., cold weather, frequent hot baths, fragrances, detergents) Emollient creams, topical corticosteroids²⁴; oral agents for severe cases²⁵
Bullous impetigo	Staphylococcus aureus	Superficial vesicles progress to flaccid bullae that rupture; collarette of scale surrounding blister at periphery of lesion; tends to affect trunk, extremities and moist, intertriginous areas; does not scar, systemic symptoms uncommon²⁶	Topical mupirocin (Bactroban) or retapamulin (Altabax); for more extensive disease or inability to tolerate topical therapy, may use amoxicillin/clavulanate (Augmentin), cephalexin (Keflex), dicloxacillin, doxycycline, or trimethoprim/sulfamethoxazole²⁶
Erythema multiforme	Immune mediated, often secondary to infection (specifically herpes simplex virus and Mycoplasma pneumoniae), may also be secondary to drugs and other causes	Trunk, limb, and face distribution, erythema multiforme minor limited to the skin, erythema multiforme major involves mucosal membranes; skin lesions < 3 cm in diameter; two concentric, colored rings surround dusky central zone; affects < 10% of body surface area, often elevated C-reactive protein level²⁷	Supportive care; if caused by a drug, discontinue that agent; if secondary to herpes simplex virus, consider antiviral therapy; corticosteroids may be used in severe cases, although controlled studies are lacking²⁸
Herpes	Herpes simplex virus 1 and 2	Fever, pruritus,¹⁹ maculopapular and vesicular rash^29,30; lesions may appear on areas in contact with oral herpes (e.g., herpetic whitlow), in areas prone to bodily contact (e.g., herpes gladiatorum), or on sites of previous atopy (e.g., eczema herpeticum³¹)	Acyclovir, famciclovir, or valacyclovir (Valtrex)³⁰
Measles	Measles virus	Respiratory spread; presents with fever, cough, coryza; Koplik spots (white papules) may present on buccal mucosa before maculopapular rash that starts on head and spreads distally Complications include pneumonia, keratoconjunctivitis, encephalomyelitis³²	Supportive treatment; vitamin A supplementation; measles may be prevented with routine childhood immunization; measles cause 100,000 deaths per year, worldwide³²
Rocky Mountain spotted fever	Rickettsia rickettsii, transmitted by infected tick (e.g., American dog tick, Rocky Mountain wood tick)	History of a tick bite (50% to 60% of patients), headaches, fever, fatigue, nausea, photophobia; rash starts with blanching, erythematous macules and papules on wrist and ankles, spreads centripetally; may ulcerate Complications include congestive heart failure, dysrhythmia, seizures, nerve palsies³³	Doxycycline; preventive measures include avoiding tick-infested habitats, tick repellant, full body skin examinations after exposure to areas with ticks³³
Scabies	Sarcoptes scabiei hominis³⁴	Linear distribution of papules corresponding with mite burrows; typical distribution includes hands, feet, skinfolds, genitalia; intense pruritus, worse at night; mites can be visualized in skin scrapings by microscope³⁵	Permethrin cream 5% (Elimite); wash all clothing, bedding, and towels in hot water; treat close contacts³⁵
Stevens-Johnson syndrome	Delayed-type hypersensitivity reaction usually associated with drugs	Fever, malaise prodrome; painful skin and mucous membrane (i.e., eye, mouth, and genital) lesions; erythematous skin with blister formation and flat atypical target lesions; pulmonary, renal, and hepatic involvement common; < 10% of skin surface area involved³⁶	Discontinue causative drug; refer to specialized units (e.g., burn centers); may consider corticosteroids, intravenous immunoglobulin, and/or cyclosporine A³⁶
Varicella (chickenpox)	Varicella zoster virus	Generalized, itchy, vesicular rash; fever, malaise; may cause pneumonitis, hepatitis, encephalitis, skin rash may become secondarily infected³⁷; rash starts on face and trunk and spreads to rest of body; starts with macules and progresses to papules and vesicles; lesions visible in all stages at the same time as each other; symptoms last four to seven days³⁸	May use acyclovir within 24 hours of rash onset, or later in severe cases or in patients who are immunocompromised³⁷; prevent with vaccination; avoid aspirin, may consider corticosteroids