Tinea capitis is a superficial fungal disease caused by dermatophytes infecting the scalp and hair. It occurs mainly in children and can be transmitted through direct or indirect contact (haircutting tools, etc.). There are four types of ringworm: ringworm yellow, ringworm white, ringworm black, and ringworm pustulosis, depending on the causative fungus and clinical manifestations.
1. Clinical characteristics
(1) Ringworm yellow
The causative agent is Trichophyton rubrum or ringworm. The initial damage is a small follicular pustule, which turns into a yellow scab after drying. The typical damage is a disc-shaped sulfur yellow ringworm scab with a ratty odor and a central hair penetration. After healing, it leaves an atrophic scar and causes permanent hair loss.
(2) Tinea alba
The causative agent is mainly Microsporum ferrocytidis or Microsporum canis. The lesions are round or irregular-shaped grayish-white scaly patches, and the hair is broken at 3-5 mm from the scalp, with a white sheath at the root of the hair. It can heal spontaneously during puberty and leaves no traces.
(3) Tinea nigra
The causative organisms are Trichophyton purpureus and Trichophyton rubrum. The rash is small, scaly dots that break off from the scalp and form small black dots at the roots of the hair follicles. Tinea nigra can occur in children and adults.
(4) Tinea suppurativa
It can be caused by microsporidia or Trichophyton rubrum, or by increased inflammation of Tinea albicans or Tinea nigra. In the early stage, it is a purulent folliculitis or pustular damage, and later it forms a carbuncle-like abscess with a soft surface and multiple openings resembling a honeycomb, and a small amount of pus is discharged when squeezed.
2.Laboratory examination
(1) Direct fungal microscopy
Ringworm yellow is the mycelium and arthrospores inside the hair, and ringworm yellow is the antler-like mycelium and spores inside the scab; ringworm white is the dense pile of small round spores outside the hair; ringworm black spot is the chain spores inside the hair.
(2) Wood’s lamp examination
The yellow ringworm fluoresces in dark green, the white ringworm fluoresces in bright green, and the black spot ringworm does not fluoresce.
Differential diagnosis
1.Seborrheic dermatitis: It is a scaly patch with oil, without hair breakage, and may be accompanied by hair loss and erythematous scaly damage at the site of seborrhea on the face, mostly in adolescence and adults.
2, head psoriasis: the rash is silvery white scaly plaque, clear boundary, hair is bundled, no hair loss broken hair, other parts can be found typical psoriasis skin lesions.
【Treatment】
1. Ashwamycin combination therapy.
(1) Oral administration of ashwagandha, 15-20mg/(kg.d), 0.6-0.8g/d for adults, divided into 3 oral doses, for 3-4 weeks.
(2) Application: 5% to 10% sulfur ointment, 2.5% iodine tincture or 1% ketoconazole, etc., for 1 to 2 months.
(3) Shampoo: 1 time daily. Haircut once every 1 to 2 weeks, can be used 2% ketoconazole lotion (Celebrex) to wash the hair.
(4) Disinfection: disinfection of daily necessities.
2.When ashwagandha is not used, you can use.
(1) Terbinafine, 62.5mg for those who weigh <20kg >40kg, 250mg/d; take orally once a day for 4-8 weeks.
(2) Itraconazole 200mg/d for adults and 2-5mg/(kg.d) for children for 4-6 weeks or more.
(3) Patients with impetigo should be given antibiotics along with antifungal drugs, and corticosteroids may be applied appropriately for severe and extensive lesions.