Favus of Scrotum Due to Trichophyton rubrum in Immunocompetent Patients: A Clinical, Mycological and Ultrastructural Study

PURPOSE

To characterize the clinical and mycological features of favus of scrotum due to Trichophyton rubrum.

METHODS

A single-site prospective study was carried out in an outpatient dermatology clinic. Microscopic examination and fungal culture were done using skin scrapings. Scales on the scrotum were stained with PAS and visualized by microscopy, including in vivo reflectance confocal microscopy (RCM). Two strains were analyzed by RAPD typing. Scutular lesions were fixed for scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

RESULTS

Cultures of the scale from the scrotum and/or groin in all patients showed a growth of T. rubrum. T. rubrum strains from scrotum and groins in one patient were demonstrated as the same strain by RAPD typing. The average age of patients was 34.1 ± 12.78 years. The mean course was 8.2 ± 5.07 days. All the patients received only topical treatment for 2 weeks without recurrence. Direct smear, calcofluor-white staining and in vivo RCM study of the scrotal favus in patients showed a massive number of septate branching hyphae, while fewer septate hyphae in scales in the groin. Abundant hyphae were found only in the outer layer of the stratum corneum of the scrotum under SEM and TEM with intact bilateral cell walls, and normal nucleus, liposomes and reticulum. Few distorted hyphae structures, cell wall degeneration, degenerated cytoplasm and the autophagy phenomenon could be seen in scales from groin under TEM.

CONCLUSIONS

Scrotal favus due to T. rubrum is still a true infection, which most often occurred in immunocompetent patients.

Tinea capitis caused by Trichophyton rubrum mimicking favus

Favus is an uncommon form of tinea capitis (TC) currently seen in geographic areas with poor sanitation and limited access to health care such as emerging nations. Several variants of this condition have been described including one exhibiting a plaque composed of parchmentlike material. The makeup of this plaque has not been described. Tinea capitis is rare in adults, particularly when the infectious agent is Trichophyton rubrum, and affected patients often exhibit comorbidities associated with diminished immune surveillance. This case report describes an elderly woman with TC due to T rubrum mimicking a rare form of favus.

Scalp demodicidosis mimicking favus in a 6-year-old boy

Demodex folliculorum and Demodex brevis are obligatory ectoparasites of the pilosebaceous unit in humans. Although most people are infested with these mites, only a small number develop clinical symptoms of demodicidosis. We report a case of demodicidosis in a 6-year-old boy who had lesions on the scalp, forehead, neck, and anterior chest for 18 months. Our clinical diagnosis at the time was favus. The microscopic examination of the hair in a 10% potassium hydroxide preparation showed no fungal spores or hyphae, but many eggs and adult mites of D folliculorum. The patient was treated with oral ivermectin and topical permethrin, and the lesions resolved completely. Demodicidosis is a rare disease that can clinically mimic favus and other crusted scalp dermatoses in children.

Tinea capitis favosa due to Trichophyton schoenleinii

A case of a tinea capitis caused by Trichophyton schoenleinii is presented. It involves a 6-year old Tunisian boy that had presented with diffuse scaling of the scalp misdiagnosed as psoriasis and was treated unsuccessfully with keratolytic shampoos for two years. Tinea favosa due to Trichophyton schoenleinii was confirmed by mycological examination. He was successfully treated with griseofulvin for 6 weeks and topical application of imidazole. Trichophyton schoenleinii is an important anthropophilic dermatophyte that causes tinea favosa. It is transmitted by contagion between humans and is currently endemic in Africa. Ringworm is still frequent in Tunisia, but favus is becoming exceptional due to improvements in living conditions and hygiene.

[Chronic favus caused by infection with Trichophyton schönleinii]

A 25-year-old female patient from Kosovo presented with a slowly progressive cicatricial alopecia which had started when she was 6 years old. Her brother in Kosovo had similar lesions. At the erythematous border of the hairless area, crusts, erosions and pustules were apparent. Mycological examination identified Trichophyton schönleinii, the causative pathogen of favus. Histological examination revealed hyphae and showed no features suggestive of other causes of cicatricial alopecia. Systemic terbinafine combined with topical ciclopiroxolamine resulted in rapid improvement of this disease which is seldom seen in Central Europe.

Favus due to Trichophyton mentagrophytes var. quinckeanum

We report a case of favus affecting the temporal region of the scalp in a 22-month-old boy. Mycological study of hairs and crusts identified Trichophyton mentagrophytes var. quinckeanum (T. quinckeanum), the causative agent of mouse favus. Treatment with oral griseofulvin led to healing.

[Tinea favosa. Report of a familial occurrence in Itapecerica da Serra (municipality of Greater São Paulo)]

Four cases of Tinea favosa occurred in the same family are reported in a small city of Brazil (Itapecerica da Serra--State of São Paulo). Trichophyton schoenleinii was isolated from all four cases. Treatment consisted of oral griseofulvin (10 mg/kg/day) for at least three months.

Circulating antibodies in human favus

Antibodies to <i>T. schoenleinii </i>were found in sera of favus patients by charcoal agglutination and immunodiffusion analyses.