Review Question - QID 216234

This patient presents with a pruritic boggy scalp plaque, focal hair loss, and cervical lymphadenopathy, all of which are consistent with a severe manifestation of tinea capitis known as a kerion. Kerions are treated with oral antifungals such as griseofulvin.

Tinea capitis is a fungal infection of the scalp, most commonly caused by Trichophyton and Microsporum dermatophyte species. These infections occur predominantly children. Infection occurs through direct contact of the scalp. The fungi infects the stratum corneum of the epidermis, progressing down the follicle and to the hair shaft. A kerion is a severe form of tinea capitis that is caused by immune hyperreactivity to the fungus and results in an inflammatory plaque with drainage and crusting. The patch of baldness occurs secondary to follicle destruction from the immune response. Diagnosis is often made clinically, although potassium hydroxide (KOH) slide preparation or fungal culture can be used to aid in the diagnosis. Kerions require oral antifungal agents such as griseofulvin or terbinafine. Antifungal shampoo is often co-prescribed as adjunctive therapy to prevent the spread of infection and for prophylaxis for close contacts.

Al Aboud et al. discuss how tinea capitis can be divided into two types of infections, inflammatory and non-inflammatory. The non-inflammatory type usually will not be complicated by scarring alopecia. The inflammatory type may result in a kerion and scarring alopecia.

Figure/Illustration A shows an alopecic patch within a raised, erythematous plaque (red arrows) with an overlying yellowish crust (blue arrows); these findings are consistent with a kerion.

Incorrect Answers:
Answer 1: Incision and drainage with adjunctive clindamycin is the treatment for skin abscesses, particularly those that are ≥2 cm and/or those in patients with signs of toxicity (fever, hypotension, tachycardia), multiple lesions, or surrounding cellulitis. Abscesses do not typically cause patchy focal hair loss.

Answer 3: Topical cryotherapy with liquid nitrogen is the first-line treatment for actinic keratosis, a precancerous skin lesion that predominates in sun-exposed areas. Exam features of actinic keratoses include thickened, erythematous papules/plaques with overlying adherent white scales. Actinic keratoses do not cause patchy hair loss but often appear in areas of existing hair loss due to increased skin exposure to ultraviolet radiation. Furthermore, children are less likely to get actinic keratoses.

Answer 4: Topical ketoconazole is an appropriate treatment for seborrheic dermatitis, a fungal infection that predominates in sebaceous gland-rich tissues (scalp, face, trunk). It presents with pruritic, erythematous patches with an overlying yellow greasy scale, but this disease does not classically produce focal hair loss. Furthermore, kerions require systemic therapy rather than topical because topical has been shown to be ineffective.

Answer 5: Topical minoxidil treats androgenetic alopecia, also known as male or female pattern hair loss, through vasodilator properties that promote hair follicle proliferation. This patient has a focal area of hair loss secondary to a fungal infection, not male/female pattern hair loss. Androgenetic alopecia typically presents with hair loss near the vertex.

Bullet Summary:
A kerion is a severe presentation of tinea capitis that is typically diagnosed clinically and and treated with oral antifungals such as griseofulvin or terbinafine.