Etiology of erythema nodosum.

One hundred patients with biopsy-proven erythema nodosum were studied at Ramathibodi Hospital from 1982 to 1992 to find out the etiology of this disease. Eighty-eight were females while twelve were males, with an age range from 6 to 72 years old (mean, 31 years old). Abnormal laboratory findings in these patients included elevation of erythrocyte sedimentation rate (76.9%), increase anti-streptolysin-O titer (10.7%), abnormal chest roentgenogram (16.7%), positive tuberculin test (50%). The cause of erythema nodosum is still unknown in a large group of patients, and it was found only in twenty-eight patients (28%). Twelve patients had tuberculosis, seven had history of antibiotic administration, six probably had streptococcal infection and the other three had Behcet's disease.

Clinical and histopathological features of secondary syphilis.

Fifty-four patients with secondary syphilis were studied in regard to the clinical manifestations, response to treatment and histopathology of the skin lesions. The correlation between the skin lesions and histopathology, between the duration of skin lesions and VDRL titer, between type of skin lesions and VDRL titer were also determined. The clinical manifestations varied from macular, maculopapular, papular, papulosquamous and urticarial lesions. The hair loss usually occurred on the scalp, but the eyebrows or even total body hair loss could occur. The response to treatment was good, only one patient relapsed. The histopathology was related to the clinical manifestations, there was sparse inflammatory cell infiltration in the dermis in macular lesions, but more dense infiltration as well as more epidermal change in papular and papulosquamous lesions. There were significant correlation between the duration of skin lesions and VDRL titer, but no correlation between types of skin lesions and VDRL titer.

Topical steroid induced chronic demodicidosis.

We report a 39-year-old female patient who developed pruritic erythematous telangiectatic patches with scaly follicular papules on the neck and upper chest for 4 years. Ten per cent potassium hydroxide preparation of skin scrapings revealed Demodex folliculorum. Histology showed three Demodex mites in one of the hair follicles. She was treated with a topical steroid without improvement. The skin lesions and Demodex mite disappeared after a single application of 1 per cent gamma benzene hexachloride but twice daily application of 1 per cent gamma benzene hexachloride for 2 weeks was needed to prevent recurrence.