A 7 years old boy presented with painful boggy swelling of the scalp, multiple sinuses with purulent discharge, easily pluckable hairs and lymph nodes enlarged in the occipital region. Which one of the following would be most helpful for diagnostic evaluation?
Ans. c. KOH mount (Ref: Fitzpatrick 7th/1811-1814; Roxburgh's 17th/41)In a 10 years old boy, who presents with painful boggy swelling of the scalp, multiple sinuses with purulent discharge, easily pluckable hairs and lymph nodes enlarged in the occipital region, the diagnosis suggests Kerion (Tirion capitis). Tinea capitis is best diagnosed by KOH mount.Tinea CapitisDermatophytosis of the scalp and associated hairMost commonly found in pre-pubertal children between 3 to 14 years of ageMost commonly caused by Microsporum canis > Trichophyton tonsurans (never caused by Epidermophyton)Pathogenesis:Ectothrix pattern: Fungus grows completely within the hair shaft, replacing the intrapilary keratin, leaving the cortex (cuticle surface) intact.Endothrix pattern: Infection establish in perifollicular stratum corneum, spreading around and into the hair shaft. Cortex (cuticle surface) is breached.Clinical features: KerionIt is a hypersensitivity reaction to infection with Microsporum canis (MC)Ranges from pustular folliculitis to kerion, which is boggy inflammatory tender mass studded with broken hairs, follicular orifice oozing with pus and easily pluckable hairsPruritus, pain, fever, occipital and posterior cervical lymphadenopathy and scarring alopecia may occur.Diagnosis:Diagnosis is made by first examining scale and hair on a microscope slide in potassium hydroxide (KOH) wet mount. It is a single most important test for diagnosis.Treatment:Oral griseofulvin (20-25 mg/Kg/day) is the drug of choice.Topical ketoconazole, Povidone iodine, zinc pyrithione and selenium sulfide are only adjuvant treatment.
Bacterial culture
Biopsy
KOH mount
Patch test