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New Treatments for Lichen Spinulosus

This uncommon disorder occurs principally in children and more frequently in boys with liken, spinulosis. The cause is unknown. The lesions consist of sharply circumscribed irregular plaques of spiny, keratinous projections that protrude from the orifices of the pilosebaceous canals. Plaques may occur anywhere on the body and are often distributed symmetrically on the trunk, elbows, knees, and extensor surfaces of the limbs. Although sometimes erythematous, the lesions are usually skin colored. They are readily palpable and represent keratotic follicular plugs. Lichen spinulosus is easily differentiated from keratosis pilaris because the latter lesions are never grouped to form plaques.

Treatment is usually unnecessary. For patients who regard the eruption as a cosmetic defect, keratolytic agents such as salicylic acid ointment (3-7%), urea-containing lubricants (10-25%), and retinoic acid preparations are often effective in flattening the projections.

Keratosis pilaris is a moderately common papular eruption may vary in extent from sparse lesions over the extensor aspects of the limbs to involvement of most of the body surface; typical areas of involvement include the upper extensor arms and the thighs, cheeks, and buttocks. The lesions may resemble gooseflesh; they are noninflammatory, scaly, follicular papules.

Irritation of the follicular plugs occasionally causes folliculitis. Because the lesions are associated with and accentuated by dry skin, they are often more prominent during the winter. They are more frequent in patients with atopic dermatitis and are most common during childhood and early adulthood, tending to subside during the 3rd decade of life. Mild or localized eruptions respond to lubrication with a bland emollient; more pronounced or widespread lesions require

Pityriasis lichenoides is encompasses pityriasis lichenoides et varioliformis acuta (PLEVA, Mucha-Habermann disease), which tends to develop acutely, and pityriasis lichenoides chronica (PLC), which follows a chronic course. The designation of pityriasis lichenoides as acute or chronic may more properly refer to morphologic appearance of the lesions, which is often hemorrhagic or necrotic in PLEVA, than to the duration of the disease. In a series of 89 pediatric cases, no correlation was found between the type of lesion at the onset of the eruption and the duration of the disease. Many patients have both acute and chronic lesions simultaneously, and transition of lesions from one form into another occurs occasionally.

Clinical Manifestations.

PLC presents with generalized, multiple, asymptomatic 3-5-mm brown-red papules that are covered by a grayish mica-like scale. A useful clinical sign is the easy detachment of the adherent scale, revealing a shining surface. Lesions may be asymptomatic or may cause minimal pruritus and occasionally become infiltrated, vesicular, hemorrhagic, and crusted. Individual papules become flat and brownish over 2-6 wk, ultimately leaving a hyperpigmented or hypopigmented macule. Scarring is unusual.

PLEVA presents with an abrupt eruption of numerous papules that have a vesiculopustular and then a purpuric center, are covered by a dark adherent crust, and are surrounded by an erythematous halo. Constitutional symptoms of fever, malaise, headache, and arthralgias may be present for 2-3 days after the initial outbreak. Lesions are distributed diffusely on the trunk and extremities, as in PLC. Individual lesions heal within a few weeks, sometimes leaving a varioliform scar, and successive crops of papules produce the characteristic polymorphous appearance of the eruption. The condition is generally self-limited from several weeks to months. The histopathologic changes of PLEVA reflect its more severe nature compared with PLC.

A rare form of PLEVA has been described as presenting with fever and ulceronecrotic plaques up to 1 cm in diameter; those are most common on the anterior trunk and flexors of the proximal upper extremities. Arthritis and superinfection of cutaneous lesions with Staphylococcus aureus may also develop. The ulceronecrotic lesions appear within papules of PLEVA.

Treatment.

In general, pityriasis lichenoides should be considered a benign condition that does not alter the health of the child. A lubricant to remove excessive scaling may be all that is necessary if the patient is asymptomatic. The most appropriate treatment includes erythromycin (30-50 mg/kg/24 hr for 2 mo) in combination with natural sunlight.

This benign, self-limited eruption consists of a continuous or discontinuous linear band of papules in a zosteriform distribution. The primary lesion is a flat-topped, red to violaceous papule covered with fine scale. Aggregates of these papules form multiple bands or plaques. In black patients, the lesions may be hypopigmented. The cause and explanation for the linear distribution are unknown. The eruption evolves over a period of days or weeks in an otherwise healthy child, remains stationary for weeks to months, and finally remits without sequelae. Symptoms are usually absent; some children complain of itching. Nail dystrophy may occur when the eruption involves the posterior nail fold and matrix.

Lichen striatus is occasionally confused with other disorders. The initial plaque may resemble papular eczema or lichen nitidus until the linear configuration becomes apparent. Linear lichen planus and linear psoriasis are usually associated with typical individual lesions elsewhere on the body. Linear epidermal nevi are permanent lesions that often become more hyperkeratotic and hyperpigmented than those of lichen striatus. A lubricating lotion containing menthol and camphor or a mild corticosteroid preparation provides sufficient relief when pruritus is a problem.

POROKERATOSIS.

This rare, chronic, progressive disease is inherited as an autosomal dominant trait. Several forms have been delineated: solitary plaques, linear porokeratosis, hyperkeratotic lesions of the palms and soles, disseminated eruptive lesions, and superficial actinic porokeratosis. The last form, probably induced by excessive sun exposure, occurs more commonly in women. Other types of porokeratosis are more common in males and begin during childhood.

PAPULAR ACRODERMATITIS OF CHILDHOOD (GIANOTTI-CROSTI SYNDROME).

This distinctive eruption is occasionally associated with malaise and low-grade fever but few other constitutional symptoms. The incidence peaks in early childhood. Occurrences are usually sporadic, but epidemics have been recorded. The skin lesion is a monomorphous, usually nonpruritic, dusky or coppery red, flat-topped, firm papule ranging in size from 1-5 mm. The papules appear in crops and may become profuse but remain discrete.

ACANTHOSIS NIGRICANS.

This is characterized by hyperpigmented, velvety, hyperkeratotic plaques that are most often localized to the neck, axillae, inframammary areas, groin, inner thighs, and anogenital region. The histologic changes are those of papillomatosis and hyperkeratosis rather than acanthosis or excessive pigment formation. Acanthosis nigricans has classically been associated with obesity; drugs such as nicotinic acid; endocrinopathies, including diabetes mellitus, Addison disease.