Dermatologica Sinica

: 2020  |  Volume : 38  |  Issue : 4  |  Page : 232--235

Terra firma-forme dermatosis involving the genitalia: Three pediatric case reports

Hsiao-Yu Li1, Hsiu-Chin Chen1, Yu-Hung Wu2,  
1 Department of Dermatology, Mackay Memorial Hospital, Taipei, Taiwan
2 Department of Dermatology, Mackay Memorial Hospital, Taipei; Department of Medicine, Mackay Medical College, New Taipei City, Taiwan

Correspondence Address:
Dr. Yu-Hung Wu
Department of Dermatology, MacKay Memorial Hospital, No. 92, Sec. 2, Zhongshan North Road, Taipei, 10449


Terra firma-forme dermatosis is a rare acquired keratinization disorder. Patients present with dirt-like brownish plaques on the neck, trunk, and limbs. It is often confused with dermatitis neglecta, confluent and reticulated papillomatosis, and acanthosis nigricans. Reportedly, it affects children, but genital involvement is rare. We describe three cases of uncircumcised boys with genital involvement, two of which had extragenital involvement. They all had good hygiene. Two underwent skin biopsy, and pathological examination showed papillomatosis and alternating keratinization in the stratum corneum. The disease can be diagnosed clinically by wiping off the lesions with 70% isopropyl alcohol pads, instead of water or soap.

How to cite this article:
Li HY, Chen HC, Wu YH. Terra firma-forme dermatosis involving the genitalia: Three pediatric case reports.Dermatol Sin 2020;38:232-235

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Li HY, Chen HC, Wu YH. Terra firma-forme dermatosis involving the genitalia: Three pediatric case reports. Dermatol Sin [serial online] 2020 [cited 2023 Mar 23 ];38:232-235
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Full Text


Terra firma-forme dermatosis (TFFD) is an acquired and benign condition, first described by Duncan et al. in 1987.[1] It is characterized by dirt-like brownish plaques on the neck and trunk of patients, even with proper hygiene. The diagnosis can be made directly if the lesions can be scrubbed-off using a 70% isopropyl alcohol pad. Genital involvement is rarely reported. Herein, we report three pediatric cases.

 Case Reports

Case 1

An 8-year-old boy presented with asymptomatic skin lesions on his trunk 9 months after the onset. He had no relevant medical history, such as diabetes mellitus, endocrine disease, eczema, or history of oral medication. He had been treated at several local medical clinics with keratolytic agents, such as salicylic acid and urea, as well as topical steroids and emollients. The management seemed to improve the condition, but the lesions reappeared after a few months. On physical examination, the patient was slim. The cutaneous examination showed asymmetric irregular, reticulated, and brownish papules and patches on his abdomen, inguinal area, penis, and scrotum [Figure 1]a, [Figure 1]b, [Figure 1]c.{Figure 1}

A skin biopsy was performed on his abdomen, and the histopathological analysis showed that the epidermis had alternating areas of loose or compact hyperkeratosis and papillomatosis [Figure 1]d. Granular pigmentation was noted on the surface of the stratum corneum, highlighted by melanin stain, but negative for iron stain. The dermal inflammation was minimal. The pathological findings suggested the diagnosis of TFFD.

The patient stated that he attempted to scrub-off the lesions everyday using body soap and water, but he could not get rid of them. After the diagnosis was confirmed histopathologically, we performed the alcohol scrub-off test on the follow-up visit. We were able to remove the lesions by rubbing them vigorously using 70% isopropyl alcohol pads [Figure 1]e.

Case 2

A 10-year-old healthy boy presented with asymptomatic skin lesions occurring for months. Cutaneous examination revealed lichenified verrucous plaques on his penile shaft [Figure 2]a. Based on the physical examination, the clinical impression was lichen simplex chronicus. The result of the skin biopsy performed on the penile skin revealed hyperkeratosis and mild papillomatosis with budding yeast spores in the stratum corneum [Figure 2]b, highlighted by periodic acid–Schiff (PAS) and Gomori methenamine silver stains. Skin scrapings for fungal culture revealed the growth of Aspergillus and Candida parapsilosis, which was considered commensal flora. Most lesions were scraped-off using a scalpel when we performed the KOH test during the follow-up [Figure 2]c. The clear lesion sites were then treated with sertaconazole (2%) cream twice a day. One month later, the skin on the penile shaft went back to normal.{Figure 2}

Case 3

A slim 7-year-old boy without any relevant medical history reported the onset of brownish skin lesions since he was 5 years old. He started to bathe by himself when he was 6 years old. He had noticed that the skin lesions did not rub off even after washing with soap and water every day. Cutaneous examination revealed checkerboard-like brownish papules and plaques on his nape, bilateral axillae, inguinal area, and penile shaft [Figure 3]a, [Figure 3]b, [Figure 3]c. Dermoscopy revealed polygonal brownish hyperpigmentation [Figure 3]d. Based on previous experience, we performed the alcohol wipe test. Indeed, the lesions could be scrubbed-off using 70% isopropyl alcohol pads, leaving behind an area with erythema [Figure 3]e. Accordingly, TFFD was confirmed, without the need for skin biopsy. Topical urea cream (10%) was then prescribed for rest of the areas. After using the keratolytic cream, the lesion improved, without recurrence at the 6-month follow-up.{Figure 3}


We describe three pediatric cases of TFFD with genital involvement. The patients were all uncircumcised boys (age ranging from 5 to 10 years of age, with a mean age of 7.6 years), with reportedly proper personal hygiene. Patients said that they took a bath daily. In all three cases, the lesions could be removed by vigorously rubbing with 70% isopropyl alcohol pads or scraping with a surgical blade. We followed up these boys for 2 years, 7 months, and 6 months, respectively. Only the boy in Case 1 presented occasional recurring lesions on his trunk.

TFFD was first described by Duncan et al. in 1987.[1] The name was derived from the Latin terms terra firma, meaning “solid land.” It is easily confused with dermatosis neglecta, which occurs in individuals with poor hygiene. The disorder is characterized with reticulated dirt-like macules and patches on the neck, trunk, and especially skin folds, such as the axillae, umbilicus, and pubic areas.[2],[3],[4] Dermoscopic changes are unstructured, large polygonal brown-to-black macules or scales, arranged in a mosaic or tile-like pattern, interrupted in furrows.[2] Histological findings are unspecific; whorled orthokeratosis, mild papillomatosis, acanthosis, and minimal dermal inflammation can be observed. Therefore, the diagnosis can be made clinically if the lesions can be scrubbed-off using isopropyl alcohol, but not water.

Most of the case series reported similar incidence in male and female patients,[3],[5],[6] although our cases were all involving boys. The disease seems to affect individuals of all ages (from 3 months to 72 years of age), but previous reports seem to be consistent with a higher prevalence in children and young adults.[4],[6],[7] In a large retrospective study in 2018 by Aslan et al., of 79 patients with TFFD, 88.6% were children with an average age of 10.4 years.[7] However, genital involvement in any of the cases they reported was not mentioned.

All of our male patients had lesions involving the genitalia. We found a case in the literature reported by Chen et al.,[8] in which a healthy 9-year-old boy presented with reticulated brownish plaques symmetrically distributed on the dorsal and lateral sides of the prepuce. Electron microscopy revealed filamentous keratin, pigment granules, and desmosomal attachments among incremental keratin lamellae and immature corneocytes. The boy did not tolerate the irritative alcohol pads, and the dirt-like lesions responded to 1-week treatment of cotton swabs soaked in 0.1% ethacridine lactate solution, followed by 0.1% tacrolimus ointment. We summarized the cases with genital involvement in [Table 1]. Notably, in all these cases, the boys were uncircumcised. Nevertheless, the case number is too small, and the relationship between uncircumcision and TFFD needs further confirmation.{Table 1}

The main differential diagnoses for TFFD are acanthosis nigricans and confluent and reticulated papillomatosis (CARP). They share similar pathological features of hyperkeratosis and papillomatosis. Although the clinical distributions and presentations are different, co-existing CARP and TFFD have been reported previously.[9] In most conditions, TFFD can be distinguished using an alcohol wipe test.[10] However, lesions of CARP wiped off by 70% alcohol pads have been observed.[11] Under a dermoscope, CARP has been found to have different features than those of TFFD, characterized by poorly defined borders, white scales, and sulci and gyri patterns.[12] In contrast, CARP responds to systemic therapy, but TFFD does not require oral medication.[6],[13]

The pathogenesis of TFFD still remains obscure[7] and is considered a disorder of delayed keratinization and accumulation of melanin and subsequent compact scales and dirt within the epidermis.[2],[3],[14] Few studies revealed sun exposure as a triggering factor, with the frequent onset of lesions in the warm summer months and intense sun exposure.[3],[6] However, in our three cases, the skin lesions all appeared on the trunk or skinfolds, suggesting that the lesions are less likely related to sun exposure. A few reports described comorbidities.[6],[7] Berk[6] retrospectively reported two of the most common comorbidities in 31 patients: atopic dermatitis (AD) (38.7%) and acne (22.6%). Neri et al.[14] also revealed an association with AD. In their observational study, 49.1% of the pediatric patients with AD had TFFD, whereas 27.5% of those without AD had TFFD (odds ratio = 2.08, 95% confidence interval 1.019–4.238). According to the reports, the defective keratinization in AD may be a risk factor for delayed keratinocyte maturation present in TFFD.[6],[14] Akkash et al.[4] described an obese 19-year-old female with concomitant presentation of TFFD and acanthosis nigricans on the neck. The patient had a history of insulin resistance and hyperprolactinemia due to pituitary microadenoma. She had brown dirt-like papillomatous plaques on the neck and dark brown hyperkeratotic plaques, with a velvety surface in both axillae. Some dirt-like areas suggestive of TFFD on the neck could be removed by vigorously rubbing with alcohol pads. When biopsied, occasionally, yeast spores might be found by PAS stain, with Malassezia furfur as the most commonly identified fungus.[4]

Although the second patient had a fungal infection caused by Aspergillus and C. parapsilosis, the pathological features were still consistent with TFFD. Candida albicans is the most common pathogen causing balanoposthitis and accounts for 35% of infectious balanitis. Aridoğan et al. reported 11.7% of yeast colonization in an uncircumcised boy (mean age of 5.8 ± 3.4 years), predominantly with C. albicans (55.5%), followed by M. furfur (33.3%).[15] They also found 1.2% of colonization by C. parapsilosis on the penile glans of the circumcised men. The clinical presentation of this boy was very different from candidiasis or aspergillosis. The fungi only appeared in the superficial layer of the stratum corneum. The dermal inflammation was mild, and no neutrophil infiltration was present either in the epidermis or dermis. Hence, we assumed that the fungi were secondarily colonized organisms.


TFFD is uncommon and more often observed in children. Genital involvement is rare and may be difficult to diagnose clinically. The “alcohol wipe test,” by which these dirt-like dermatoses can be removed, is a useful tool to establish the diagnosis as an adjunct to skin biopsy. It is important for dermatologists and pediatricians to recognize this disease and its clinical presentation.

Ethical approval

This study was approved by the IRB of MacKay Memorial Hospital, the approval no.19MMHIS197e obtained on September 3rd, 2019. The patient consent was waived by the IRB.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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