**4. Protozoal infection of scalp**

### **4.1. Syphilitic alopecia**

**3.2. Favus**

206 Hair and Scalp Disorders

and a few spores.

**3.3. Kerion**

Favus or tinea favosa is the most severe form of tinea capitis. It is caused by *Tricophyton schoenleinii*. The disease frequently occurs in children and is seen rarely in adults. If untreated, the disease persists forever. Favus is seen almost exclusively in Africa, the Mediterranean and

The most common clinical manifestations on the scalp are yellowish cup-shaped crusts termed scutula, which surround the infected hair follicles. The scutula have an unpleasant mousy odour. Besides the scalp, it may involve glabrous skin, hairy regions and nails. If not treated properly, the lesion advances peripherally and it can leave scarring alopecia [45, 46]. The diagnosis is confirmed by direct mycological examination and culture. A greyish-green fluorescence may be observed with Wood's lamp examination. Optical microscopy with KOH preparation shows invasion by the fungus, hyphae parallely arranged to the axis, air spaces

In presence of scaly patches without alopecia, favus is misdiagnosed as seborrheic dermatitis,

The treatment of tinea favosa lies on the combination of an oral and topical antifungal agents. The local treatment consists in cutting of hair around the alopecia patches and applying once or twice a day of antifungal imidazol [shampoo, foam gel, lotion and spray]. Griseofulvin

Kerion celsi [KC] [so-called deep tinea capitis] is an uncommon inflammatory presentation of tinea capitis [TC], which appears as a boggy, large inflammatory painful mass studded with broken hairs, pustules and, often, purulent drainage from its surface (**Figure 5**). Hair loss is frequently seen in KC. It is usually solitary but multiple lesions may be found. Reactive lymphadenopathy, especially cervical or suboccipital, is a very common associated feature. KC often occurs in children but it has been described in elderly patients [49–51]. The higher

the Middle East and, rarely, in North America and South America [44].

terbinafine and itraconazole could be used in systemic therapy [44, 45].

psoriasis, tinea amiantacea or lichen planus [47, 48].

**Figure 5.** Boggy, large inflammatory painful plaque lesion is seen.

Syphilis is a sexually transmitted disease caused by *Treponema pallidum*. Syphilitic alopecia [SA] is an uncommon feature of secondary syphilis with an incidence of 2.9–11.2% [57]. The physical examination findings include numerous non-scarring, non-inflammatory, irregular in size without defined borders, 'moth-eaten' patches of alopecia of the scalp [58]. The eyebrows and beard may also be involved. SA can be seen with other mucocutaneous symptoms of secondary syphilis. Hair loss usually occurs late in the secondary syphilis, about 8–12 weeks after the first signs of secondary syphilis [59].

According to the patterns of McCarthy made in 1940, secondary SA is classified into two types: symptomatic SA and essential SA. The other cutaneous manifestations of syphilis is not seen in essential SA. Essential SA, characterised by alopecia without any other visible syphilitic lesions on the scalp, may appear as one of three different clinical patterns: 'motheaten' alopecia, diffuse alopecia and mixed pattern of alopecia [58, 60]. The 'moth-eaten' pattern alopecia [alopecia syphilitica] is considered the most common and characteristic form of secondary syphilis [61, 62].

The diagnosis of SA is confirmed by both patient's sexual history and positive serological tests for RPR and TPPA. The histopathology findings of SA usually include a normal epidermis with areas of follicular hyperkeratosis. While the number of anagen follicles are reduced markedly, the number of catagen and telogen follicles increase. A perivascular and perifollicular [especially in the peribulbar region] lymphocytic dermal infiltration with scattered plasma cells is observed in some cases [63].

The differential diagnosis of 'moth-eaten' alopecia includes alopecia areata, trichotillomania and tinea capitis except from syphilis [64]. Under trichoscopy black dots, focal atrichia, hypopigmentation of hair shaft and yellow dots are observed in the hair loss region. Alopecia areata, tinea capitis and trichotillomania differ from SA with absence of exclamation hair, coma hair, flame hairs or v-sign, respectively [57].

The antisyphilitic treatment with a weekly dose of 2.4 million units of benzathine penicillin for 3 weeks or procaine penicillin 600,000 units i.m. daily for 10 days leads to complete resolution of alopecia. Hair growth is observed about 6–12 weeks after the start of the treatment [57, 65, 66].
