History and clinical findings: A 26-year-old man fell acutely ill with fever (39 degrees C), rigor, dry cough, headache and pain in the neck and limbs. Ambulant treatment with amoxycillin, later cefuroximaxetil, worsened his general condition. At admission to hospital he had, over his trunk and limbs, cocarde-like, erythematous efflorescences up to 2 cm in diameter with central elevations and blisters. Additional acute bronchitis, pharyngitis, stomatitis, tonsillitis, conjunctivitis and urethritis indicated extensive mucosal involvement.
Investigations: Significant findings were: 9900/microl WBC, ESR 57 mm at one hour, C-reactive protein 160 mg/l, capillary pO2 6.4 kPa, pCO2 4.2 kPa. Mycoplasma serology (days 1, 8, 15) took a typical course. Chest radiogram showed an interstitial infiltrate on day 5.
Diagnosis: Respiratory Mycoplasma infection with interstitial pneumonia and exudative erythema multiforme.
Treatment and course: Because infection with an atypical pathogen was suspected, antibiotic treatment was changed to erythromycin and, at the suggestion of the dermatologist and ophthalmologist, local treatment (erythromycin, dexamethasone and dexpanthenol) was begun. Mycoplasma serology was first positive on day 3. The fever had disappeared on day 6 and the rash had regressed. Blood gases and blood picture were normal by day 8. The patient was discharged on day 18, after marked improvement of the skin and mucosal changes.
Conclusion: The occurrence of a rare dermatological complication of a relatively common respiratory Mycoplasma infection can, when the erythema precedes positive Mycoplasma serology, aid in the differential diagnosis.