Egyptian Journal of Dermatology and Venerology

: 2018  |  Volume : 38  |  Issue : 1  |  Page : 46--48

Bilaterally symmetrical terra firma-forme dermatosis: a diagnostic conundrum

Chetna Singla, Jyoti Budhwar, Bharat B Mahajan 
 Department of Dermatology, Venereology and Leprology, Government Medical College, Amritsar, Punjab, India

Correspondence Address:
Chetna Singla
Department of Dermatology, Venereology and Leprology, Sri Guru Ram Das Institute of Medical Sciences and Research, Amritsar (143001), Punjab


Terra firma-forme dermatosis or dermatosis neglecta is characterized by dirty brown plaques that can be removed by forceful rubbing or with an alcohol swab. Also known as Duncan’s Dirty Dermatosis, it is usually seen at the regions of the neck, trunk, and upper extremities in children as well as adults. Here we report a patient with complaints of multiple asymptomatic dirty brown-colored, flat-topped slightly raised lesions over the face in a young girl, and emphasize its unique expression. All the lesions completely disappeared with forceful rubbing using a spirit swab, with normal underlying skin without any recurrence till date.

How to cite this article:
Singla C, Budhwar J, Mahajan BB. Bilaterally symmetrical terra firma-forme dermatosis: a diagnostic conundrum.Egypt J Dermatol Venerol 2018;38:46-48

How to cite this URL:
Singla C, Budhwar J, Mahajan BB. Bilaterally symmetrical terra firma-forme dermatosis: a diagnostic conundrum. Egypt J Dermatol Venerol [serial online] 2018 [cited 2023 Mar 31 ];38:46-48
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 What’s known

Terra firma-forme dermatosis has dirty brown plaques.These plaques can be removed by rubbing them with an alcohol swab.Differential diagnosis can include plane warts and seborrheic keratosis.Terra firma-forme can occur at any age.


Terra firma-forme dermatosis (TFFD) is an acquired and idiopathic dermatosis [1]. It is the appearance of dirty brown slightly raised lesions that cannot be washed off with soap but can be easily removed by rubbing with an alcohol swab. Usually, the lesions of TFFD do not pose any medical threat to the patient, but they are cosmetically unsightly and cause psychological distress to the patient.

Lesions of TFFD were first described by Duncan and colleagues in 1987, and hence the name ‘Duncan’s Dirty Dermatosis’. The name TFFD, that is, terra firma-forme dermatosis, is derived from the latin word ‘terra firme’, which means dirty land [1]. It is a rarely reported and often misdiagnosed disease, and therefore its true prevalence and incidence is usually underestimated and still unknown. It can affect people of any age and sex, youngest case reported being that of a 4 months old child [2]. On examination, the lesions are dirty brown in color, slightly raised plaques that are asymptomatic but can be localized to a certain area or present extensively. Any part of body can be affected. These lesions cannot be removed with either soap or water but can be easily removed with the help of a cotton soaked in 70% ethyl alcohol [3]. Differential diagnosis includes acanthosis nigricans, confluent and reticulate papillomatosis of Gougerot and Carteaud, pityriasis versicolor, epidermal nevi, and dirty neck syndrome of atopic dermatitis [4].

 Case report

A 15-year-old girl presented to the tertiary care center with crusting of the both upper and lower lips since the last 3–4 days associated with burning sensation. On careful physical examination, multiple lesions that were bilaterally symmetrical were present in the form of dirty brown-colored adherent crusts over forehead, bilateral cheeks covering the malar area, and the temples ([Figure 1] and [Figure 2]). On inquiring, she gave a history of such asymptomatic dirty brown plaques over the face gradually progressive in nature and present for the last 5 months. Lesions started over the forehead and further lesions started appearing over both cheeks. When asked about cleanliness, she reported trying to clean the lesions with water only, but with no success. Throughout this period of 5 months, she never used soap, although she reported the presence of acne before the onset of the present lesions. Under considerable distress, as the lesions were present over the face, she had consulted many physicians but with no diagnosis and had given up hope of getting treated for the same. After thorough examination, differential diagnosis of the plane warts, seborrheic keratosis and TFFD were kept. Biopsy was not done as it was refused by the patient. Our diagnosis of TFFD in this patient was confirmed when the lesions completely cleared off following rubbing with a spirit swab, with completely normal underlying skin ([Figure 3],[Figure 4],[Figure 5]). The relieved and considerably happier patient was sent home with instructions to use a spirit swab in case of any recurrence of TFFD. No recurrence of TFFD was seen.{Figure 1}{Figure 2}{Figure 3}{Figure 4}{Figure 5}


TFFD has afflicted mankind throughout the ages but was only first described in the medical literature in the 20th century. It derives its name from the Latin phrase terra firma meaning dry land (dirt), thus implying dirt-like dermatosis. However, it has also been referred to as Duncan’s Dirty Dermatosis in honor of the physician who initially described this condition in Houston in 1987 [5]. TFFD is characterized by brown, dirt-like discoloration that cannot be removed by bathing with water or rubbed off with routine detergent soap. This condition has most often been seen in children, but also in adults, with equal incidence in men and women. TFFD most often involves the neck and trunk but has also been reported on the scalp [6] and the pubic region [7].

The cause of TFFD is not yet fully understood. It is believed that the lesions arise as a consequence of a delay in the maturation of keratinocytes, with melanin retention and a sustained accumulation of sebum, sweat, corneocytes, and microorganisms in regions where hygiene measures are less rigorous (e.g. neck, trunk, navel, and flanks), leading to insufficient exfoliation and the formation of a highly adhesive, compact dirty crust [3],[8]. Therefore, when this condition is suspected, firm, persistent pressure should be applied while rubbing the skin with alcohol.

The differential diagnosis of the condition, which has a varied clinical presentation, should include confluent and reticulated papillomatosis of Gougerot and Carteaud [9], pityriasis versicolor, acanthosis nigricans, pseudoacanthosis nigricans, dermatitis artefacta, and, in certain localized cases, seborrheic keratoses, epidermal nevi [10], and dirty neck syndrome of atopic dermatitis.


Awareness of TFFD facilitates prompt diagnosis and thereby prevents unnecessary biopsy and extensive endocrine evaluation. Patient with extensive TFFD and their families must be educated regarding cleaning the skin at home. After removal of pigmentation with isopropyl alcohol, discoloration usually does not recur. It is very satisfying for both the patient and the clinician to see a cosmetically bothersome skin condition disappear with simple application of isopropyl alcohol. Patients feel reassured knowing that they do not have a serious illness or a permanently disfiguring condition.

 What’s new

Bilaterally symmetrical involvement of face.Depressed mentation of the patient.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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