Untitled Review | Dermatol Pract Concept 2015;5(3):8 29 DERMATOLOGY PRACTICAL & CONCEPTUAL www.derm101.com Introduction Terra-firma forme dermatosis is a benign condition with a characteristic clinical appearance of brown or black hyper- keratotic plaques or papules. The application of 70% iso- propyl alcohol is both diagnostic and therapeutic for this disorder. We describe ten patients who presented with terra- firma forme dermatosis that usually affected skin creases and that resolved after wiping with 70% isopropyl alcohol pads. Case series Terra-firma forme dermatosis was diagnosed in ten Cauca- sian patients whose clinical characteristics are summarized Terra firma-forme dermatosis: A report of ten individuals with Duncan’s dirty dermatosis and literature review Tanya Greywal1, Philip R. Cohen2 1 School of Medicine, University of California, San Diego, CA, USA 2 Department of Dermatology, University of California, San Diego, CA, USA Key words: dermatosis, Duncan’s dirty dermatosis, isopropyl alcohol, terra firma, terra firma-forme Citation: Greywal T, Cohen PR. Terra firma-forme dermatosis: A report of ten individuals with Duncan’s dirty dermatosis and literature review. Dermatol Pract Concept 2015;5(3):8. doi: 10.5826/dpc.0503a08 Received: March 27, 2015; Accepted: April 9, 2015; Published: July 31, 2015 Copyright: ©2015 Greywal et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: None. Competing interests: The authors have no conflicts of interest to disclose. All authors have contributed significantly to this publication. Corresponding author: Philip R. Cohen, MD. Email: mitehead@gmail.com Background: Terra-firma forme dermatosis, also known as Duncan’s dirty dermatosis, is a benign skin condition that presents as dirt-like plaques in patients of all ages. Purpose: We describe a series of ten patients that presented with terra-firma forme dermatosis. Methods and Materials: We reviewed PubMed for the following terms: dermatosis, Duncan’s dirty dermatosis, isopropyl alcohol, terra firma, and terra firma-forme dermatosis. We also reviewed papers containing these terms and their references. Results: The diagnosis of terra firma-forme dermatosis was confirmed in all patients who had com- plete resolution of each lesion after the application of 70% isopropyl alcohol. Conclusions: Terra-firma forme dermatosis is easily diagnosed and treated with 70% isopropyl al- cohol. It is important to recognize this benign dermatologic condition since it can be confused with other cutaneous disorders. Therefore, in order to avoid unnecessary referrals, biopsies, blood tests, and medications, we suggest a trial of wiping the skin lesion with 70% isopropyl alcohol pads when the diagnosis of terra-firma forme dermatosis is considered. ABSTRACT 30 Review | Dermatol Pract Concept 2015;5(3):8 with 70% isopropyl alcohol pads. Our patients included nine men and one woman. The men’s ages ranged from 54 to 86 years, with a mean age of 70 years. The woman was 59 years of age. Most of the patients were unaware of their asymp- in Table 1. The morphology of each lesion was similar and consistent with terra-firma forme dermatosis: brown and/or black plaques or papules or both. Final diagnosis was con- firmed with the resolution of each lesion after firm rubbing TABLE 1. Clinical characteristics of ten patients with terra firma-forme dermatosis [1,2] Case Age (yrs) Race Sex Location Hx of NMSC Other Medical Conditions 1 54 C M Right and left inguinal folds Right suprapubic region No None 2 58 C M All interspaces between the first through fourth toes on both feet No • Addison disease • Chronic lymphocytic leukemia • Chronic inflammatory demyelinating polyneuropathy • Hypothyroidism 3 61 C M Skin folds on the anterior neck Yes: SCC • Atrial fibrillation • Coronary artery disease • Depression • Generalized anxiety disorder • Hypertension 4 66 C M Concha of right ear Yes: SCC • Depression • Hyperlipidemia • Hypertension • Narcolepsy • Prostate cancer • Urge urinary incontinence • Vocal cord palsy 5 66 C M Central chest Yes: BCC, SCC • Anxiety • Gout • Hypercholesterolemia • Hypertension • Insomnia • Macular puckering of retina 6 73 C M Occipital scalp No • Meningioma 7 82 C M Right distal neck fold Right and central chest Left inguinal fold Yes: BCC, SCC • Benign prostatic hyperplasia • Chronic lymphocytic leukemia • Hypertension • Obstructive sleep apnea 8 82 C M Right and left inguinal folds Yes: BCC • Coronary artery disease • Diverticulosis • Hypertension • Prostate cancer 9 86 C M Right and left subclavicular chest Yes: BCC • Melanoma 10 59 C W Right chest, skin fold beneath the right breast No • Anxiety • Asthma • Breast cancer • Hypertension • Hypothyroidism • Insomnia • Osteoporosis 1. Abbreviations: BCC, basal cell carcinoma; C, Caucasian; Hx, history; M, man; NMSC, nonmelanoma skin cancer; SCC, squamous cell carcinoma; W, woman; yrs, years 2. The morphology of all lesions was similar, consisting of brown or black plaques or papules. All lesions resolved with firm applica- tion of 70% isopropyl alcohol Review | Dermatol Pract Concept 2015;5(3):8 31 1 and 2) or flexor areas or skin folds (Figure 3); less common locations included in-between the toes (case 2) (Figure 4), the right ear concha (case 4) (Figure 5), and the occipital scalp (case 6). Only one patient had involvement of two distant sites, the chest and the groin (case 7). In addition, most of tomatic dermatosis. All patients practiced good hygiene and showered a minimum of every other day or daily. In addition, with the exception of one patient (case 4), all were capable of reaching the affected locations while showering. Most of the lesions (except case 6) were located on concave sites (Figures A B C D Figure 1. Terra firma-forme dermatosis in an 82-year-old man (case 7). A brown plaque is present on the concave skin of the right distal neck (A). Resolution of the brown plaque after rubbing with several 70% isopropyl alcohol pads (B). The isopropyl alcohol pads before (C) and after (D) use, showing evidence of the brown pigmentation that was removed. [Copyright: ©2015 Greywal et al.] Figure 2. The initial appearance of a brown plaque on the subcla- vicular chest of an 86-year-old man (case 9) (A). Resolution of the brown plaque after rubbing with 70% isopropyl alcohol (B). [Copy- right: ©2015 Greywal et al.] A B 32 Review | Dermatol Pract Concept 2015;5(3):8 the patients had other medical conditions that were most likely a reflection of their age and not a predisposing factor to terra-firma forme dermatosis. Several patients had a his- tory of non-melanoma skin cancer (cases 3, 4, 5, 7, 8, and 9), while only one patient had a history of melanoma (case 9). Discussion Terra firma-forme dermatosis is a benign condition of acquired dirt-like plaques. The name, “terra firma,” is derived from the Latin words meaning “solid land” [1,2]. It has also been referred to as Duncan’s dirty dermatosis since the condition was first described by Duncan, Tschen, and Knox in 1987 [3]. This condition affects people of all ages, with some reports of a higher incidence in children and young adults [1,3-7]. Terra firma-forme dermatosis does not Figure 3. An 82-year-old man (case 8) with a hyperkeratotic brown plaque in the inguinal fold, as seen on initial presentation (A). Clearing of the lesion in the inguinal fold after aggressive wiping with 70% isopropyl alcohol pads (B). [Copyright: ©2015 Greywal et al.] A B Figure 4. Clinical presentation of terra firma-forme dermatosis in a 58-year-old man (case 2). Brown plaques affecting the interspaces be- tween the first through fourth toes, bilaterally (A). Clearing of terra firma-forme dermatosis after wiping with 70% isopropyl alcohol pads (B). [Copyright: ©2015 Greywal et al.] A B Figure 5. Terra firma-forme dermatosis in a 66-year-old man (case 4). Initial presentation of black and brown papules and plaques on the concha of the right ear (A). Resolution of all pigmentation after the application of 70% isopropyl alcohol (B). [Copyright: ©2015 Greywal et al.] A B Review | Dermatol Pract Concept 2015;5(3):8 33 new lesions on his subclavicular chest within three months after the original lesions had been completely removed [2]. In this situation, additional wiping with isopropyl alcohol is recommended [2,8]. Some patients may require weekly application of isopropyl alcohol to maintain resolution or for prophylaxis [2,8]. Consistent moisturizing to the effected skin is important to prevent xerosis after regular treatments with isopropyl alcohol. Conclusion Terra firma-forme dermatosis presents as asymptomatic, brown, dirt-like plaques. All of our patients presented with this typical morphology, and their lesions successfully resolved after the application of 70% isopropyl alcohol. While terra firma-forme dermatosis typically presents on the neck, face, trunk, and ankles, our patients’ lesions pre- dominantly involved skin folds. It is important to consider the possibility of this benign dermatologic condition and the many locations in which it can present since it can readily mimic other cutaneous disorders. Therefore, in order to avoid unnecessary referrals, biopsies, blood tests, and medications, we suggest a trial of wiping the skin lesion with 70% iso- propyl alcohol pads when the diagnosis of terra firma-forme dermatosis is entertained. References 1. Akkash L, Badran D, Al-Omari AQ. Terra firma-forme dermatosi. Case series and review of the literature. J Dtsch Dermatol Ges 2009;7:102-7. 2. Ozturk F, Kocabas E, Ertan P, Ermertcan AT. Terra firma-forme dermatosis. Cutan Ocul Toxicol 2010;29:303-5. 3. Duncan WC, Tschen JA, Knox JM. Terra firma-forme dermatosis. Arch Dermatol 1987;123:567-9. 4. Guarneri C, Guarneri F, Cannavo SP. Terra firma-forme dermato- sis. Int J Dermatol 2008;47:482-4. 5. Pavlovic MD, Dragos V, Potocnik M, Adamic M. Terra firma- forme dermatosis in a child. Acta Dermatovenerol Alp Pannonica Adriat 2008;17:41-2. 6. Berk DR, Bruckner AL. Terra firma-forme dermatosis in a 4-month-old girl. Pediatr Dermatol 2011;28:79-81. 7. Ratcliffe A, Williamson D, Hesseling M. Terra firma-forme der- matosis: it’s easy when you know it. Arch Dis Child 2013;98:520. 8. Erkek E, Sahin S, Cetin ED, Sezer E. Terra firma-forme dermatosis. Indian J Dermatol Venereol Leprol 2012;78:358-60. 9. Berk DR. Terra firma-forme dermatosis: a retrospective review of 31 patients. Pediatr Dermatol 2011;29:297-300. 10. Thomas RS, Collins J, Young RJ, Bohlke A. Atypical presenta- tions of terra firma-forme dermatosis [published online ahead of print January 30 2015]. Pediatr Dermatol 2015. doi: 10.1111/ pde.12505. 11. Tavli YU, Mevlitoglu PI, Toy H, Unal M. Terra firma forme dis- ease. J Paediatr Child Health 2012;48:1046-7. 12. Berk DR, Mutizwa MM. Comment regarding the histopathology of terra firma-forme dermatosis. J Cutan Pathol 2012;39:300-1. have a predilection for any particular gender, although our patients were predominantly men [4,6]. It is also unrelated to any known genetic condition or familial inheritance [8]. Terra firma-forme dermatosis usually presents as asymp- tomatic black or brown, dirt-like plaques [1,4,6,9,10]. It may also have a papillomatous, verrucous, or reticulate appear- ance [6,11]. Lesions are typically located on the neck, face, trunk, and ankles, although they may involve any area of the body [1,2,4,5,7-9]. One study observed that terra firma- forme dermatosis had a predilection for heavier patients and concave skin areas, which is consistent with the majority of our patients’ presentations [12]. The distribution of terra firma-forme dermatosis varies; it can be localized, general- ized, bilateral, or unilateral [4,7-9]. Lesions appear in patients with normal hygiene, yet are resistant to scrubbing with soap and water [1,3,10,11]. In addition, investigators have sug- gested that terra firma-forme dermatosis most often presents during the warmer months of the year [3,4]. The diagnosis of terra firma-forme dermatosis is classi- cally based upon clinical presentation and subsequent lesion resolution after the application of 70% isopropyl alcohol [1-4,6,9,11]. Aggressive rubbing with 70% isopropyl alcohol pads is sometimes required to achieve the appropriate shear- ing forces to remove all pigmentation [2]. Biopsies are not frequently performed. If tissue is obtained, hematoxylin and eosin staining will show lamellar hyperkeratosis with com- pact orthokeratotic whorls and an absence of parakeratosis, acanthosis, papillomatosis, keratotic material between the papillae, and melanin deposition not only within the basal layer but also in the hyperkeratotic areas [1-6,8,10,11]. Numerous keratin globules can also be visualized throughout the stratum corneum with toluidine blue staining [1,2,5]. The differential diagnosis for terra firma-forme derma- tosis includes acanthosis nigricans, confluent and reticulate papillomatosis, dermatosis neglecta, dirty neck syndrome of atopic dermatitis, epidermal nevi, epidermolytic hyperkera- tosis, granular parakeratosis, ichthyosis, idiopathic decidu- ous skin, omphalith, pseudoacanthosis nigricans, seborrheic keratosis, and tinea versicolor [1-6,8-11]. The etiology of terra firma-forme dermatosis is unclear [1-5,11]. Many believe this condition is caused by delayed keratinocyte maturation, which leads to the retention of keratinocytes and melanin within the epidermis [3,4,6,8,10]. This disordered keratinocyte buildup and compaction with surrounding sebum and dirt may ultimately explain the hyperkeratosis and hyperpigmentation clinically seen in terra firma-forme dermatosis [3,8,10]. The treatment of terra firma-forme dermatosis consists of the application of 70% isopropyl alcohol; it is both diagnostic and therapeutic [1,3-5,10,11]. Occasionally, lesions may recur after the initial complete removal of all hyperpigmentation; indeed, one of our patients (case 7) developed easily treated