Ghai Essential Pediatrics8th

Fig. 25.11: Comedones: Keratin plugs that form within follicular ostia

Arrangement and Configuration of Lesions

Arrangement and configuration of skin lesions can help in diagnosis (Table 25.1).

Table 25.1: Arrangement and configuration of skin lesions

Sites of Predilection

Sites of predilection are important for dermatological diagnosis (Fig. 25.12).

GENODERMATOSES

Genodermatoses are a group of inherited single gene cutaneous disorders that manifest themselves wholly or in part in the skin, mucous membranes, hair and nails.

lchthyoses

Ichthyoses are a heterogeneous group of disorders characterized by the presence of fish-like scales. The etiology is heterogeneous (Table 25.2). They are classified as follows:

i.Ichthyosis vulgaris

ii.X-linked ichthyosis

iii.Autosomal recessive ichthyosis

Segmental vitiligo

Lichen planus

Scabies

Diaper dermatitis Psoriasis

Fig. 25.12: Sites of predilection of common skin disease

a.Lamellar ichthyosis

b.Nonbullous ichthyosiform erythroderma

iv.Keratinopathic ichthyosis

The chief clinical features of icthyosis are listed in Table 25.3 and Figs 25.13 to 25.18.

Treatment

Hydration (by immersing in water) and immediate lubrication with petroleumjelly or urea containing creams and lotions are useful.

Keratolytic agents (hydroxyacids, propylene glycol and salicylicacid) are usedwhenlesionsaremoderatelysevere. Oralretinoids (acitretin)areadministeredin collodion baby, severe cases of lamellar ichthyosis and in keratinopathic ichthyosis. A short course of topical steroid and antibiotic combination is used in eczematized skin.

Palmoplantar Keratoderma

This condition may be inherited or acquired. The hereditarykeratodermas are causedbya gene abnormality

Fig. 25.13: lchthyosis vulgaris: Large scales on extremities that are attached at the center and turned up at the edge

Fig. 25.14: X-linked ichthyosis: Large dark brown adherent scales without sparing of flexure

that results in abnormal keratin. Inheritance is either autosomal dominant or autosomal recessive (Table 25.4).

The condition is characterized by thickening of skin of palms and soles (Fig. 25.19), which usually manifests at birth or in the first few months of life. Mutilating variants are characterized by massive thickening and mutilation (Fig. 25.20). Sometimes keratoderma extends onto the dorsae of hands and feet (keratoderma transgrediens).

Therapy for keratoderma includes the topical use of emollients, keratolytics (salicylic acid 6-12%, urea 30-40%), retinoids and vitamin D (calcitriol). Systemic retinoids (acitretin) are used in mutilating variants.

Epidermolysis Bullosa

These are a heterogeneous group of disorders defined by a tendency to develop blisters even on trivial trauma. The common clinical features are listed in Table 25.5. EB

Fig. 25.15: Collodion baby: Baby is ensheathed in a shiny lacquer­ like membrane

Fig. 25.16: Lamellar ichthyosis: Large pasted scales with continuous rippling around ankle

Fig. 25.18: Keratinopathic ichthyosis, Brownish, warty, broad linear plaques

Table 25.4: Classification of hereditary palmar and plantar keratoderma

Fig. 25.19: Palmoplantar keratoderma, Autosomal dominant variant thickening of skin of soles

Fig. 25.17: Nonbullous ichthyotic erythroderma, Diffuse erythema, with fine scales

Fig. 25.20: Palmoplantar keratoderma: Autosomal recessive massive thickening and mutilation

simplex and dominant dystrophic EB are inherited in an autosomal dominant manner. Junctional EB and recessive dystrophic EB are inherited as autosomal recessive.

Treatment

General measures include avoiding friction and trauma, wearing soft well ventilated shoes and gentle handling. Prompt and appropriate use of antibiotics for injuries and infected lesions is necessary. The role of vitamin E and phenytoin is doubtful. Surgerymaybe requiredfor release of fused digits, correction of limb contractures and esophageal strictures.

Ectodermal Dysplasias

Ectodermal dysplasias comprise a large, heterogeneous group of inherited disorders that are defined by primary

defects in the development of 2 or more tissues derived from embryonic ectoderm. The disorders can be classified based on inheritance (autosomal dominant, autosomal recessive, and X-linked) or by structures involved (hair, teeth, nails, sweat glands).

Anhidrotic Ectoderma/ Hypoplasia

This X-linked disorder presents with intolerance to heat, episodes of high fever due to reduced ability to sweat (hypohidrosis) because of few sweat glands. The facies is districtive with prominent forehead, thick lips and a flat bridge of the nose. Additional features include thin, wrinkled, and dark-colored periorbital skin. The hair are sparse, light-colored, brittle and slow-growing. The teeth may be absent (hypodontia) or malformed (small, conical) (Fig. 25.23).

Table 25.7: Classification of vascular birthmarks

Treatment

Salmon patch. No treatment required.

Infantile hemangioma. Small lesionsresolvespontaneously. Large symptomatic lesions need treatment with systemic steroids in the proliferative phase. Propranololused under supervision shows dramatic result. Pulsed-tunable dye laser is useful for cosmetic results.

Port wine stain: Cosmetic camouflage; laser ablation with pulsed-tunable dye laser.

Lymphangioma: Surgery,carbondioxidelaser,radiofrequency ablation

ECZEMATOUS DERMATITIS

Eczematous dermatitis manifest clinically in acute phase as papulovesicular lesions, and in chronic phase as thickened dry and sometimes lichenified skin.

Atopic Dermatitis

Atopic dermatitis is an acute, subacute or chronic relapsing, endogenous eczema, characterized by dry skin and pruritic, recurrent, symmetric dermatitic lesions. The etiology is unclear. Genetic predisposition is an important factor but the inheritance pattem has not been ascertained. Immunological changes include elevated IgE levels, increased levels of allergen specific IgE and abnormalities of lymphocytes.

Clinical Features and Diagnosis

In children, two distinct patterns of AD are seen. Infantile pattern Atopic dermatitis may have onset in infancy, after 3 monthsof age. The chief features are itchy, erythematous papulovesicles, seen on the face (Fig. 25.27), but may become generalized. The lesions clear by 18 months of age in 40% and evolves into the childhood pattern in the rest.

Childhood pattern The childhood pattern is char­ acterized by dry lichenified and crusted plaques, seen mainly on antecubital (Fig. 25.28) and popliteal fossa, the neck and face. Most (70%) clear by 10 yr of age. Common complications include the occurrence of superimposed bacteriaorviral (herpessimplex,molluscum contagiosum) and fungal infections.

The diagnosis of atopic dermatitis is facilitated by diagnostic criteria (Table 25.9).

Treatment

Parents and the childshouldbeeducatedabout the disease and its chronic course. There is limited role for dietary restriction. Breastfeeding decreases the chance of developing atopic dermatitis.

Patients are educated to avoid scratching, avoid contact with irritants, likewoolensandchemicals. Mild soaps and cleansing lotions are used. Measures to reduce exposure to house dust mite, e.g. using barriers on pillows and mattresses, regular vacuuming of rooms may help. There

Fig. 25.25: Infantile hemangioma: Soft bright red nodule with pale stippling

Fig. 25.26: Port wine stain: Light pink to deep red macule

Fig. 25.27: Infantile eczema: Papulovesicular lesions on the face

is no contraindication to vaccination except in children specificallyallergic to eggs, in whom influenza and yellow fever vaccines are avoided.

Acute eczema is treated with wet dressing; topical steroids and topical and oral antibiotics, are used when indicated. The role of oral antihistaminics is controversial.

Chronic eczema is managed by hydration followed by application of emollients like petrolatum. Topical steroids are sometimes combined with keratolytic agents like

salicylic acid (in lichenified lesions). It is preferred to use the least potent steroid, which reduces symptoms. Potent steroids should be avoided on face and genitalia. Topical immunomodulators like tacrolimus and pimecrolimus are useful because of their steroid sparing action and rapid reduction in itching. Oral antihistaminics might be used to break the itch-scratch cycle. Narrow band UVB, psoralens with UVA (PUVA) and oral cyclosporine are useful in resistant cases.

Infan tileSeborrheic Dermatitis

The onset of symptoms is usually in the first 4 weeks of life, with erythema with yellow-orange scales and crusts (Fig. 25.29) on the scalp (cradle cap). Eczematous lesions may be present in the major flexures and trunk. The illness is self limiting and generally resolves by 12 weeks. Ma1assezia Jurfur is incriminated in pathogenesis. The crusts of cradle cap should be removed and this can be facilitated by pretreatment with an oil. Application of 2% ketaconazole shampoo, mild topical steroid or 1 % pimecrolimus cream hastens subsidence.

Diaper Dermatitis

This is irritant dermatitis in infants due to prolonged contact with feces and ammonia (produced by the action of urea splitting organisms in urine). The area in contact with diapers (the convexity of buttocks) shows moist, glazed erythematous lesions with sparing of depth of flexures (Fig. 25.30). Diaper dermatitis is prevented by keeping area clean and dry and avoiding the use of disposable absorbent diapers. The washed cotton diapers should be rinsed in dilute lemon juice. Emollients and mild topical steroids with antifungal agents are useful in the acute phase.

Fig. 25.30: Diaperdermatitis: Moist, glazed erythematous lesionswith sparing of depth of folds

DISORDERS OF SKIN APPENDAGES

Acne Vulgans

Acne vulgaris is a polymorphic eruption due to inflammation of the pilosebaceous units. This is a common illness, affecting 80% adolescents who present with a polymorphic eruption of open and closed comedones, papules, pustules, nodules andcystson a background of oily skin (Fig.25.31). The lesions usually heal with pitted scars.

Etiology

The etiology is multifactorial and includes:

Increased sebum secretion. Sebaceous glands in these patients show enhanced sensitivity to circulating androgens leading to increased sebum secretion.

Microbial colonization. Propionibacterium acnes (a normal commensal) is most commonly implicated.

Occlusion of pilosebaceous orifice. Pilosebaceous orifice is occluded by keratinplugs leading to retention of sebum and consequent growth of microbes, setting up a vicious cycle.

Variants

Infantile acne is caused by maternal hormones and presents at birth, lasting for up to 3 yr. It is more common in males and lesions are similar to adolescent acne.

Acne conglobata is a severe form of acne characterized by abscesses, cysts and intercommunicating sinuses.

Drug induced acne. Drugs causing acne include steroids, androgens, antituberculous and anticonvulsant drugs. The eruption consists of monomorphic lesions of papules or pustules.

Therapy

Therapy of acne is summarized in Table 25.10. In addition, oil and oil based skin care products should be avoided. There is no restriction with regard to use of soaps and cleansers. No dietary restrictions are usually needed.

* Oral retinoids maybeused in females with moderateor severe lesions under supervision

Alopecia Areata

The condition affects children and young adults, who present with discoid areas of noncicatricial alopecia with exclamation mark hair at periphery (Fig. 25.32). The common sites are scalp, eye lashes and eye brows. In alopecia totalis there is total absence of terminal hair on scalp, while alopecia universalis is characterized by total loss of terminal hair from scalp and body (Fig. 25.33). Ophiasis is a band like pattern of hair loss from periphery of the scalp. Nails may occasionally show fine pitting and thinning of the nail plate.

Spontaneous remission is common. Initially, the regrowing hairs are grey, but regain color over period of time. Poor prognostic features include onset in childhood, ophiasis, association with atopy and widespread alopecia. The principles of treatment are outlined in Table 25.11.

Miliaria

Miliaria is due to obstruction and rupture of eccrine sweat ducts resulting in spillage of sweat into adjacent tissue. Its clinical features depend the level of rupture.

Fig. 25.32: Alopecia areata: Noncicatricial, noninflammatory discoid lesions with exclamation mark hair at periphery

Fig. 25.33: Alopecia totalis: Total loss of terminal hair from scalp and body

Table 25.11: Treatment of alopecia areata

Miliaria crystallina. Usually seen during high fever. Is characterized by tiny, noninflamed superficial vesicles (Fig. 25.34).

Fig. 25.34: Miliaria crystallina: Tiny, noninflamed superficial vesicles

Miliaria rubra. Characterized by small erythematous papules commonly surmounted by vesicles.

Miliaria profunda. Characterized by large erythematous papules.

Therapy ofmiliaria issupportive. Patients should avoid humidity and wear cotton clothes. Itching can be avoided with calamine lotion and topical steroids.

PAPULOSQUAMOUS DISORDERS

Psoriasis

Psoriasis is a chronic, recurring dermatosis which may have onset in childhood or adolescence (type I psoriasis) and in adults (type II psoriasis). Type I psoriasis is usually characterized by a positive family history, severe disease, prominent Koebner phenomenon, association with HLA cw6 and prolonged course, requiring aggressive therapy.

Psoriasis is apolygenictrait. At least 9differentpsoriasis susceptibility loci (PSORS 1-9) have been identified in

genome linkage studies. The condition is often triggered by physical trauma, infections (P hemolytic streptococci, HIVinfection)anddrugs(lithium,NSAIDs, antimalarials). T lymphocytes are believed to be important in the patho­ genesis.

Psoriasis vulgaris is characterized by well demarcated, indurated, erythematous scaly lesions. Lesions become polycyclic due to confluence and annular because of central clearing. Symmetrical involvement of knees, elbows and extensors, lower back, scalp and sites of trauma (Koebner or isomorphic phenomenon) is seen. Face and photoexposed areas are generally spared. The scales are accentuated on grating the lesion with a glass slide (Grattage test). Removal of the scales by scraping with a

glass slide reveals a glistening white membrane and on removing the membrane, punctate bleeding points become visible (Auspitz sign).

Guttate psoriasis is defined by crops of small erythematous scaly papules, predominantly on trunk. The conditions may follow an episode of streptococcal tonsillitis.

Pustular psoriasis is rare in children. Annular pustular psoriasis is characterized by sudden onset of fiery red erythema rapidly covered by cluster of very superficial creamy white pustules, which form circinate or annular lesions (Fig. 25.35).Infantileandjuvenilepustularpsoriasis is seen in infants (Fig. 25.36) and has a benign course; it is often confused with seborrheic and napkin dermatitis.

Associated Findings

Nail changes. Include pitting, thickening, subungual hyperkeratosis, onycholysis, discoloration and oil spots or staining of nail bed.

Joints 10% patients have joint involvement.

Fig. 25.35: Pustular psoriasis: Superficial pustules which coalesce to form circinate lesions

Fig. 25.36: Juvenile psoriasis: Annular or circinate lesions seen in infants