1Department of Dermatology, Hospital Alto Guadelquivir, Andújar, Jaén, Spain; 2Department of Dermatology, Complejo Hospitalario de Granada, Granada, Spain *Corresponding Author e-mail: ismenios@hotmail.com لوحات صبغية مثل الرتاب على الرقبة واخلط األبيض لفتاه عمرها أثين عشر عاما بابلو فرنانديز-كريهيو و ريكاردو رويز فيالفريدي Dirt-Like Hyperpigmented Plaques on the Neck and Linea Alba of a 12-Year-Old Girl Pablo Fernández-Crehuet1 and *Ricardo Ruiz-Villaverde2 interesting medical image A 12-year-old girl was referred to the outpatient dermatology department at the Hospital Alto Guadalquivir, Andújar, Spain, in April 2015 with a five-month history of asympt- omatic dirt-like hyperpigmented plaques on her neck and linea alba [Figure 1]. The patient had been previously treated with adapalene 0.1% cream twice a day for one month after the eruption was diagnosed as pseudoacanthosis nigricans by a general paediatrician. However, no response to treatment was observed. Diabetes mellitus and insulin resistance were ruled out as causative factors and the patient’s medical history was unremarkable. A dermoscopic examination using the Dermlite DL3 (3 Gen Inc, San Juan Capistrano, California, USA) revealed polygonal areas of brownish pigmentation affecting the dermatoglyphs [Figure 2]. Complete and immediate resolution of the plaques was noted after firm rubbing with a 70% isopropyl alcohol swab [Figure 3]. Comment Terra firma-forme dermatosis (TFFD), also known as Duncan’s dirty dermatosis, has a distinctive clinical presentation as it generally appears as an eruption of dirt-like hyperpigmented brown plaques. TFFD is relatively common and usually occurs on the neck or posterior malleolus of children and young adults.1 There is currently some debate as to whether TFFD and dermatosis neglecta are the same entity; however, patients with TFFD generally have satisfactory hygiene habits, whereas dermatosis neglecta usually results from inadequate cleansing.2 Delay in the maturation of keratinocytes—with melanin retention and a sustained accumulation of sebum, sweat and corneocytes in areas of the body where hygiene measures may be less rigorous—might explain the appearance of TFFD. Vigorous but unsuccessful attempts at cleaning the affected areas have previously been described in the literature.2 Pathological examination of the plaques Sultan Qaboos University Med J, May 2016, Vol. 16, Iss. 2, pp. 259–260, Epub. 15 May 16 Submitted 25 Oct 15 Revision Req. 7 Dec 15; Revision Recd. 9 Dec 15 Accepted 3 Jan 15 doi: 10.18295/squmj.2016.16.02.023 Figure 1A & B: Photographs showing asymptomatic dirt-like hyperpigmented plaques on the (A) neck and (B) linea alba of a 12-year-old girl. Dirt-Like Hyperpigmented Plaques on the Neck and Linea Alba of a 12-Year-Old Girl e260 | SQU Medical Journal, May 2016, Volume 16, Issue 2 ethyl or isopropyl alcohol—although salicylic acid- based exfoliants or other keratolytic agents are sometimes recommended to accelerate normalisation of the skin.7 Unfortunately, topical corticosteroids, antimycotics and retinoids are sometimes prescribed inappropriately for cases of TFFD.8 Physicians should therefore be aware of this entity to avoid performing unnecessary skin biopsies and to ensure that they prescribe appropriate treatment. References 1. Berk DR. Terra firma-forme dermatosis: A retrospective review of 31 patients. Pediatr Dermatol 2012; 29:297–300. doi: 10.1111/j.1525-1470.2011.01422.x. 2. Martín-Gorgojo A, Alonso-Usero V, Gavrilova M, Jordá- Cuevas E. Dermatosis neglecta or terra firma-forme dermatosis. Actas Dermosifiliogr 2012; 103:932–4. doi: 10.1016/j.adengl. 2011.12.006. 3. Dalton SR, Pride H. The histopathology of terra firma-forme dermatosis. J Cutan Pathol 2011; 38:537–9. doi: 10.1111/j.1600- 0560.2011.01731_1.x. 4. Erkek E, Sahin S, Çetin ED, Sezer E. Terra firma-forme dermatosis. Indian J Dermatol Venereol Leprol. 2012; 78:358–60. doi: 10.4103/0378-6323.95455. 5. Thomas RS, Collins J, Young RJ, Bohlke A. Atypical presen- tations of terra firma-forme dermatosis. Pediatr Dermatol 2015; 32:e50–3. doi: 10.1111/pde.12505. 6. Kaminska-Winciorek G, Wydmanski J, Scope A, Argenziano G, Zalaudek I. “Neglected nipples”: Acanthosis nigricans-like plaques caused by avoidance of nipple cleansing. Dermatol Pract Concept 2014; 4:81–4. doi: 10.5826/dpc.0403a17. 7. Choudhary SV, Bisati S, Koley S. Dermatitis neglecta. Indian J Dermatol Venereol Leprol 2011; 77:62–3. doi: 10.4103/0378- 6323.74986. 8. Ratcliffe A, Williamson D, Hesseling M. Terra firma-forme dermatosis: It’s easy when you know it. Arch Dis Child 2013; 98:520. doi: 10.1136/archdischild-2012-303499. is not usually necessary unless another condition is suspected. In cases of TFFD, lamellar orthokeratotic hyperkeratosis and intra-corneal orthokeratotic whorls may be observed and dermoscopic examination will show a ‘stone pavement’ pattern characterised by polygonal areas of brownish pigmentation.3 In addition, endocrinological evaluation should be performed to rule out skin diseases associated with insulin resistance, such as acanthosis nigricans.4 The differential diagnosis of TFFD includes acanthosis nigricans, confluent and reticular papillo- matosis, tinea versicolor, ‘dirty neck’ lesions of atopic dermatitis, epidermal naevi, epidermolytic hyperkeratosis, granular parakeratosis and ichthyosis vulgaris.5,6 Treatment for these conditions is similar to that prescribed for TFFD—swabbing with 70% Figure 2: Dermoscopic image at x10 magnification showing polygonal areas of brownish pigmentation affecting the dermatoglyphs of a 12-year-old girl with asymptomatic dirt-like hyperpigmented plaques on her neck and linea alba. Figure 3A & B: Photographs of the (A) neck and (B) linea alba of a 12-year-old girl showing the complete resolution of asymptomatic dirt-like hyperpigmented plaques after firm rubbing with a 70% isopropyl alcohol swab. http://dx.doi.org/10.1111/j.1525-1470.2011.01422.x http://dx.doi.org/10.1016/j.adengl.2011.12.006 http://dx.doi.org/10.1016/j.adengl.2011.12.006 http://dx.doi.org/10.1111/j.1600-0560.2011.01731_1.x http://dx.doi.org/10.1111/j.1600-0560.2011.01731_1.x http://dx.doi.org/10.4103/0378-6323.95455 http://dx.doi.org/10.1111/pde.12505 http://dx.doi.org/10.5826/dpc.0403a17 http://dx.doi.org/10.4103/0378-6323.74986 http://dx.doi.org/10.4103/0378-6323.74986 http://dx.doi.org/10.1136/archdischild-2012-303499