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Terra firma-forme dermatosis

  • Mariacarmela Santarpia
    Affiliations
    Department of Human Pathology, Unit of Oncology, University of Messina (Italy), c/o A.O.U. “G. Martino”, Via Consolare Valeria 1, 98125 Messina, Italy
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  • Claudio Guarneri
    Correspondence
    Corresponding author. Tel.: +39 349 251 6782; fax: +39 090 292 7691.
    Affiliations
    Department of Clinical Experimental Medicine, Unit of Dermatology, University of Messina (Italy), c/o A.O.U. “G. Martino”, Via Consolare Valeria 1, 98125 Messina, Italy
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Published:February 24, 2016DOI:https://doi.org/10.1016/j.ejim.2016.02.009
      A 75-year-old woman who was positive for metastatic breast cancer and left radical mastectomy complained of two month-history of dirty-appearing skin, composed of subtle but clear-cut brown to blackish areas with a velvety texture, symmetrically involving lateral sides of trunk and proximal upper limbs, chest, abdomen and the whole dorsum (Fig. 1). The discoloration was apparently unrelated to patient's medications, whereas showers and brushings with acid liquid soap did not lead to significant improvement. On dermatological consultation, partial removing of these patches by isopropyl alcohol swabbing confirmed the clinical suspicion so she was reassured about the benignity of the disease and the easiness of treatment.
      Figure thumbnail gr1
      Fig. 1Diffuse brown-blackish hyperpigmentation of the left thorax, axilla and dorsal surface of arm, with subtle pigmentation of the abdomen.
      Alcohol swabbing reveals normal skin. Note the appearance of alcohol pad after rubbing.
      What is the diagnosis?
      Terra firma-forme dermatosis (TFFD), formerly Duncan's Dirty Dermatosis, is a benign condition whose name derives from the Latin expression terra firma, meaning ‘dirty land’.
      The true prevalence of TFFD is probably underestimated.
      According with literature, it affects a wide range of ages (4–72 years) with equal incidence in both sexes [
      • Duncan W.C.
      • Tschen J.A.
      • Knox J.M.
      Terra firma-forme dermatosis.
      ]. Most patients come to visit during the warm period of the year, someone having experienced intense sun exposure during the summer. A familial character has never been reported [
      • Guarneri C.
      • Guarneri F.
      • Cannavò S.P.
      Terra firma-forme dermatosis.
      ].
      Physical exam usually discloses asymptomatic, localized or extensive and sometimes symmetrical clear-cut areas of brownish to black hyperpigmentation, variously characterized by the presence of palpable, papillomatous plaques and focal light scaling, involving most often the neck and trunk but also affecting scalp, back, limbs, axillary, umbilical and pubic areas [
      • Duncan W.C.
      • Tschen J.A.
      • Knox J.M.
      Terra firma-forme dermatosis.
      ,
      • Guarneri C.
      • Guarneri F.
      • Cannavò S.P.
      Terra firma-forme dermatosis.
      ].
      Readily diagnosable by focal clearing using alcohol-soaked pads, thus avoiding further unnecessary evaluations (i.e. histologic examination, cultures for bacteria/fungi, hormonal assays), TFFD should be distinguished from pityriasis versicolor, Gougerot and Carteaud's reticular and confluent papillomatosis, acanthosis nigricans, and pseudoacanthosis nigricans, atopic dermatitis with post-inflammatory hyperpigmentation, frictional asymptomatic darkening of the extensor surfaces, idiopathic deciduous skin and dermatosis neglecta [
      • Duncan W.C.
      • Tschen J.A.
      • Knox J.M.
      Terra firma-forme dermatosis.
      ,
      • Guarneri C.
      • Guarneri F.
      • Cannavò S.P.
      Terra firma-forme dermatosis.
      ].
      Speculation into the pathophysiology includes an altered maturation of keratinocytes with retention of melanin and initial inadequate cleansing with build up and compaction of scales and dirt.
      Recrudescence has to be considered exceptional [
      • Guarneri C.
      • Guarneri F.
      • Cannavò S.P.
      Terra firma-forme dermatosis.
      ].

      Funding source

      None.

      Conflict of interests

      The authors state that they have no conflicts of interest.

      References

        • Duncan W.C.
        • Tschen J.A.
        • Knox J.M.
        Terra firma-forme dermatosis.
        Arch Dermatol. 1987; 123: 567-569
        • Guarneri C.
        • Guarneri F.
        • Cannavò S.P.
        Terra firma-forme dermatosis.
        Int J Dermatol. 2008; 47: 482-484