Fixed macules and target lesions may be larger and more confluent than in EM minor. Skin tenderness usually is not present. Lips may be edematous, bloody, or crusted. Bullae and shallow ulcers resembling aphthous ulcers are common. When bullae rupture, mucosal lesions become deeply erythematous erosions, often covered by gray pseudomembranous exudates.
Salivation often is increased.
Ocular complications may include corneal ulceration, anterior uveitis, panophthalmitis, corneal opacities, symblepharon formation, and blindness. Infectious causes are more common in children and are implicated more commonly in EM minor. Drugs are the major culprits in adults and in EM major. Herpes simplex infection is the most common cause in young adults and is strongly associated with recurrent EM minor. The most prevalent bacterial precipitant is Mycoplasma pneumoniae .