Wound healing (after trauma, burning, infections, surgery) is a cutaneous repair process that may result in an atrophic scar or an elevated scar compared to the surrounding skin. The latter is called a hypertrophic scar. When the scar is disproportionate to the skin lesion, it is called a keloid.

The different forms of scarring are related to individual characteristics and to wound care (e.g., injuries with secondary infections, skin tension in the wound areas). Some ethnic groups may be more prone to hypertrophic scars and keloids, especially those with melanodermic skin.

Clinically, hypertrophic scar and keloid are hard on palpation, with brownish or skin-colored lesions. The hypertrophic scar is an elevated lesion compared to normal skin and do not exceed the original scar (Figs. 8.1 and 8.2) . The keloid is a disproportionate scar, attaining a size larger than the scar caused by the original injury (Fig. 8.3) .

Diagnosis is clinical. Skin biopsy for histopathological examination should be performed when there are other diagnostic hypotheses. Proposed treatments include topical corticosteroids under occlusion, infiltration of corticosteroids, cryotherapy, or surgery. In case of surgery, it is necessary to take into account the possibility of recurrence of hypertrophic scars or keloids at the site of attempted surgical repair.

Hypertrophic scars and keloids are common among indigenous people. Traumatisms are very common because they are often exposed to the environment and secondary bacterial infection is frequent.

Lichen striatus is a rare, self-limited dermatosis , with a linear distribution along Blaschko’s line . Its etiology is unknown. Children with atopic diathesis are more susceptible to the development of this disease. Genetic and environmental (virus) factors are likely responsible for lichen striatus onset.

More than 50% of cases occur in children under 15 years old, but onset can occur at any age. It affects women more often than men.

Clinical features are characterized by small bright, whitish, or purple papules, which increase rapidly, converging in papular plates in a linear arrangement, restricted to a few centimeters in size or covering the whole affected limb (Figs. 8.4, 8.5, and 8.6) . Nails may also be affected, with permanent dystrophy (Fig. 8.7) . Mainly the disease affects the upper and lower limbs. Generally, the disease is asymptomatic, but some patients report pruritus.

Diagnosis is based on the clinical presentation. If necessary, a skin biopsy that shows a lichenoid inflammation with dyskeratotic keratinocytes may be performed.

In most cases treatment is not necessary. If there is itching, topical or intralesional corticosteroid infiltration can be prescribed. Cream and moisturizing oils should be used. The lesions regress spontaneously within 3 months to 1 year.

Interestingly, we observed 6 cases of lichen striatus in Xingu Indigenous Park, a large number considering about 400 patients were examined. The disease is common in children, with no gender preference. One patient presented digital involvement with nail dystrophy. There was no predominant ethnic group.

Endemic pemphigus foliaceus, or fogo selvagem , is a bullous disease characterized by the production of IgG antibody against anti-desmoglein 1. This antigen is located on the surface of keratinocytes in the most superficial portion of the epidermis (granular layer). This specific antibody causes the rupture of desmosomes (acantholysis), and a cleavage occurs, resulting in this bullous disease. The endemic pemphigus foliaceus is a regional disease in Brazil and is probably caused by environmental factors. Currently, the triggering of “fogo selvagem seems to be linked to the black flies (Simulium spp.), common in these areas.

Pemphigus foliaceus, unlike pemphigus vulgaris , occurs in children and young adults. There is no gender preference. People exposed to this environment, especially in rural areas, can develop fogo selvagem.

Superficial cleavage results in fragile vesicules and bullous lesions that easily rupture (Fig. 8.8) . Therefore, clinical examination will show mainly erosions, crusts, and desquamation (Fig. 8.9) . The lesion distribution is similar to that observed in seborrheic dermatitis (Fig. 8.10) . A few patients develop exfoliative erythrodermic forms. There is no mucosal involvement, as observed in pemphigus vulgaris.