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SUMMARY
Scalp infectious and infestations range from mild to extremely serious conditions.
The etiopathogenesis could be divided into fungal infections (tinea capitis), bacterial infections (impetigo, secondary syphilis), viral infections (HSV, VZV, Molluscum contagiosum), and parasite infestations (pediculosis).
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TIPS FOR DIAGNOSIS
Trichoscopy is crucial for the first instrumental approach.
Laboratory testing, such as microscopic and cultural exams, helps the clinical for differential diagnosis.
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TIPS FOR TREATMENT
Local therapy is the first approach in mild cases.
Combined therapy with topical and oral drugs may increase the cure rate in severe cases.
Possible secondary infection can be found especially due to itching.
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DON’T FORGET
They usually affect other parts of the body as an initial site and then it spreads to other areas such as the scalp, but can rarely begin directly on the scalp.
They can manifest as single or multiple lesions.
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PITFALLS AND CAUTIONS
Many hair diseases can mimic scalp infections.
Trichoscopy can be useful, but better together with the clinical and family history.
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EXPERT PEARLS
Scalp infections and infestations typically affect children.
Look always to other family members.
An immediate therapeutic approach is crucial to avoid a rare cicatricial alopecia.
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FUNGAL SCALP INFECTIONS (RINGWORM, TINEA CAPITIS)
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Tinea capitis, also known as ringworm, refers to a fungal infection of the scalp, eyelashes, and eyebrows, most often caused by the dermatophytes belonging to two genera: Trichophyton and Microsporum. The main causative agents are Trichophyton tonsurans (T. tonsurans) and Microsporum canis (M. canis).1–5
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Tinea capitis is typical of childhood (92% of fungal infections). It is mainly observed in pre-puberal age, typically in male patients (greater frequency between 3 and 7 years).1–5
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Clinically it manifests as single or multiple alopecic patches with broken hair at the follicular ostium in the endothrix type, or 1 to 3 mm from the scalp in the ectothrix type (Fig. 44.1).1,3 In the endothrix-type of Tinea capitis, dark-colored follicular ostia are observed (Fig. 44.2) (“black dots” due to the hair trapped on the surface); in the ectothrix form, the hair is broken irregularly several mm from the emergence.2 The inflammatory signs are typical of tinea due to zoophilic or geophilic dermatophytes, ranging from erythema and desquamation up to pustulation, edema, and crusty plaque lesions (Kerion). Latero-cervical lymph nodes can be appreciated during physical examination.4,5
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