Journal of Pakistan Association of Dermatologists 2003; 13 : 211-213.

Quiz What are these pIaques?

Amor Khachemoune, Shahbaz A Janjua Ayza Skin and Research Centre , Lalamusa

An 8-year-old, otherwise healthy, girl presented with 1-month history of an eruption of mildly pruritic, rough plaques over the skin of her elbows, knees and upper lateral thighs. Her personal and family medical histories were unremarkable; particularly there was no history of atopic diathesis. She denied the use of any medication in the recent past.

On physical examination, there were Figure 1 multiple, symmetrically distributed, 2 cm to 6 cm round to oval plaques comprised of multiple, grouped, monomorphous, follicular, keratotic, skin colored, 1 mm to 2 mm affecting the skin over her elbows ( Figure 1 ), knees and upper lateral thighs. Each was bearing a central, protruding, thorny, hair-like, 1-mm keratotic spine ( Figure 2 ). Although, the papules were grouped into plaques, discrete follicular, keratotic papules were Figure 2 also present in the vicinity of the plaques. The lesions were not biopsied, as the consent could not be obtained from her parents.

Address for Correspondence Dr. Shahbaz A. Janjua, MD, Ayza Skin and research Centre, Lalamusa. E mail: [email protected]

211 What are these plaques? Amor Khachemoune & S.A Janjua .

Diagnosis On histopathology, LS lesions show a Lichen spinulosus central, infundibular, keratotic plug dilating the follicle and protruding above Lichen spinulosus (LS) is a rare, the epidermal surface. Follicular idiopathic, follicular, keratotic dermatosis hyperkeratosis, parakeratosis and occurring mostly in children, adolescents acanthosis may be present. Dermal and young adults. The male to female ratio perifollicular and perivascular is 2:3. 1 No race predilection or seasonal lymphocytic infiltrate is also seen under variations have been noted. This condition light microscopy. It is pertinent to note was first recorded in the literature by that LS is histopathologically Crocker in 1883. He named it “lichen indistinguishable from . pilaris seu spinulosus.” Since then, there were few case reports until Friedman Differential diagnosis recorded 35 cases in the Philippines. 1 Differential diagnosis of LS is broad and Characterized by an acute development of includes other follicular keratotic symmetrically distributed follicular, dermatoses such as the following keratotic papules that are sharply grouped dermatoses: in round to oval plaques varying in size from 2 cm to 6 cm, LS can appear on the • Keratosis pilaris may closely mimic LS, extensor surfaces of elbows and knees, the but is a common dermatosis, of slow neck, buttocks, abdomen and the onset, appearing most commonly in the trochanteric regions. Very rarely, the first decades of life. Seasonal variation eruption can be generalized. A typical LS with winter exacerbation is another papule is 1 mm to 3 mm in diameter with differentiating point. Morphologically, it is skin-colored conical projection and a differentiated from LS by the even but central 1-mm to 2-mm keratotic spine. The diffuse distribution of smaller, keratotic eruption may be asymptomatic or only follicular papules, each with a protruding mildly pruritic. The lesions may spring up or embedded central hair, occurring simultaneously or in crops. commonly on the extensor surfaces of proximal limbs. There are many clinical Etiology and pathology subtypes with keratosis pilaris alba being Although the exact etiology of LS is the most common and differentiated from uncertain, it has been described as a keratosis pilaris rubra, another subtype, by follicular reaction pattern to various the absence of perifollicular . environmental agents such as infections, There is a frequent association of keratosis toxins, chemicals and drugs. 2 It has been pilaris with vulgaris. attributed to atopy, 3 but clear evidence is lacking. Because lesions occur on pressure • may be familial areas, trauma has been considered a cause, or acquired with acute onset but is although clinical findings do not suggest differentiated from LS by characteristic koebnerization. 1 LS is also described in reddish-orange or salmon-colored scaling, patients with HIV infection, 3,4 and in palmoplantar keratoderma and keratotic association with Crohn’s disease. 5 In short, follicular papules on the dorsal surfaces of LS remains an idiopathic dermatosis. the proximal phalanges, elbows and wrists.

212 Journal of Pakistan Association of Dermatologists 2003; 13 : 211-213.

• Darier’s disease is an autosomal debris on the bulbar conjunctiva; these are dominant genodermatosis, characterized commonly called Bitot’s spots. by the symmetrical appearance of follicular keratotic, skin-colored papules Treating LS on the seborrheic areas. The papules, Lichen spinulosus does not usually which are pruritic, ultimately turn spontaneously remit and may persist for yellowish brown and greasy. Palms are several years, if left untreated. However, commonly involved and the nails undergo the lesions may involute gradually over changes consisting of red and white several years. Treatment aims to address longitudinal stripes, ridging and nicking at the cosmetically unappealing the distal ends, and are often disfigurement caused by the disease. It pathognomonic. Mutations in the gene includes topical application of keratolytic ATP2A2 (Darier’s gene) have been agents including salicylic acid, lactic acid described to be responsible for the disease. and urea available in different The affected gene encodes for the calcium formulations and concentrations. In one pump, so the mutation alters cytosolic study, overnight application of 6% calcium levels, resulting in disruption of salicylic acid gel under occlusion for 2 the desmosomes and keratin filaments. weeks and without occlusion for 8 weeks resulted in significant reduction of the • Phrynoderma is described as cutaneous keratotic lesions. 6 Topical steroids may be manifestations of vitamin A deficiency added if pruritus is also present. In another characterized by follicular hyperkeratosis study, treatment with 12% lactic acid affecting anterior thighs and posterior lotion and triamcinolone in a moisturizing arms due to keratinization of the hair base also resulted in significant follicles giving the general appearance of improvement. 3 Topical retinoids have no “toad skin.” Vitamin A deficiency could role in treating LS. be primary, mainly due to inadequate intake, or less commonly could be References secondary to interruption with the 1. Friedman SJ. Lichen spinulosus. Clinicopathologic review of thirty-five absorption, storage and transport of the cases. J Am Acad Dermatol 1990; 22 : 261- vitamin as in celiac disease, cirrhosis of 4. the liver and surgical resection of the 2. Becker SW. Lichen spinulosus following intradermal application of diphtheria duodenum. Children with chronic toxin. Arch Dermatol Syph 1930; 21 :839- malnutrition are especially prone to the 40. effects of the hypovitaminosis A. Other 3. Strickling WA, Norton SA. Spiny eruption on the neck. Diagnosis: lichen spinulosus manifestations include night blindness, (LS). Arch Dermatol 2000; 136 : 1165-70. xerophthalmia, keratomalacia and 4. Cohen SJ, Dicken CH. Generalized lichen keratinization of the mucosal epithelia of spinulosus in an HIV positive man. J Am the gastrointestinal and urinary tracts. Eye Acad Dermatol 1991; 25 :116-8. 5. Kano Y, Orihara M, Yagita A, Shiohara T. changes are the earliest signs detected and Lichen spinulosus in a patient with consist of retinal dysfunction and xerosis Crohn's disease. Int J Dermatol 1995; 34 : of the cornea and conjunctiva. Advanced 670-1. 6. Maiocco KJ, Miller OF. Lichen disease is characterized by the presence of spinulosus: response to therapy. Cutis superficial foamy patches of epithelial 1976; 17 : 294-9.

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