P229 Three cases of easy to be misdiagnosed tinea of vellus hair

POSTER SESSION 2, SEPTEMBER 22, 2022, 12:30 PM - 1:30 PM: ABSTRACT: Vellus hair, also known as fine hair, is generally accepted that tinea of vellus hair is caused by dermatophyte infection of the vellus hair and fungal microscopy reveals the presence of mycelium and/or spores inside and outside the vellus hair. Different types of dermatophytes can cause different types of lesions. Therefore, tinea of vellus hair is easy to underdiagnose or misdiagnose in clinical practice. We report three cases of tinea of vellus hair caused by Microsporum canis. Case 1: A 24-year-old male patient with bilateral erythema with pruritus on the upper extremities for more than 1 year (A1). The patient was diagnosed with tinea of vellus hair by positive dermatoscopy (A2), fungal fluoroscopy (A3), and fungal culture of M. canis. after 9 weeks of treatment (oral itraconazole 0.2 g, 2 times/day, topical amorolfine cream 1 time/day, terbinafine cream 1 time/day), the skin of bilateral forearms basically returned to normal, and it is currently under follow-up. Case 2: A 5-year-old female patient with a rash on the root of the nose for 2 weeks (B1). She was also diagnosed with tinea of vellus hair by positive dermatoscopy (B2) and fungal fluoroscopy (B3) and fungal culture of M. canis. After 2 weeks of treatment (oral itraconazole 0.1 g, 2 times/day, topical terbinafine cream once a day), the lesions improved significantly. After 4 weeks of treatment, a few scales and scabs were still visible on the skin at the root of the nose. After 2 weeks of continued treatment, the patient's skin at the root of the nose was completely restored to normal. Case 3: 2-year-old male patient with a recurrent facial rash with scales for more than 3 months (C1). He was diagnosed with tinea of vellus hair by positive dermatoscopy (C2), fungal fluoroscopy(C3), and fungal culture of M. canis. After 2 weeks of treatment (oral itraconazole 0.1 g once every other day, bifonazole cream 1 time/d), the lesions are in improvement from the previous. And this case is still being followed up. The above three cases have been misdiagnosed as tinea simplex or eczema, and the efficacy of treatment only with topical medicines or short-term oral drugs is not good. Therefore, we take oral medicines and topical medicines for treatment, the course of treatment is long, and there are still spores and hyphae inside and outside the hair many times during the treatment period, so it is recommended that tinea of vellus hair should be treated according to the treatment plan of tinea capitis.