• Conflict of interest: None declared.

15 April 2012

Dear Editor,

Terra Firma Forme Disease (TFFD), first defined by Duncan and his collegues in 1987, is also known as Duncan's Dirty Disease. It is a rare type of keratinisation disorder with fully unidentified aetiology. While lesions look black dirt, thinly papillomatous and can not be removed by cleaning and rubbing with soap and water, they disappear totally after rubbing with 70% isopropyl or ethyl alcohol. Limited number of cases has been reported since it was diagnosed.

The 14-year-old female patient visited our polyclinic with complaints of asymptomatic thinly papillomatous brown lesions on abdomen and back for 1 year. Medical and family history of the patient was examined and no significant pathology was detected. The patient stated that the problem still recurred despite rubbing with shampoo and soap. Dermotological examination revealed dirty, hyperkeratotic and hyperpigmented papules existed especially on the abdomen, back and shoulders. (Fig. 1) It was observed that the lesions disappeared totally after rubbing with 70% of alcohol. (Fig. 2)

Figure 1.

Dirty, hyperkeratotic and hyperpigmented papules on the abdomen.

Figure 2.

The lesions disappeared after rubbing with 70% alcohol.

During histopathological examination, hyperkeratosis in the epidermis, increased pigmentation in the basal layer, oedema and mononuclear cell infiltration in papillary dermis were observed and no features were seen in periodic acid schiff coloration (Fig. 3).

Figure 3.

Hyperkeratosis in epidermis, increased pigmentation in basal layer, oedema and mononuclear cell infiltration in papillary dermis.

Lesions disappeared totally after rubbing with 70% of alcohol, and no emergence of new lesions were observed during the 8-month follow-up time.

TFFD, defined by Duncan and colleagues, is a rare keratinisation disorder of unknown aetiology.1 Most of the cases reported in literature are about child and adolescent age groups (4 months minimum and as for age maximum 72) like our patient. No familial characteristic has been reported and no relationship with bathroom habits and hygiene have been observed.2,3 The most frequent location of the disease is shoulder and back. However, some cases in which other body areas were affected have been reported.2,4 Lesions are generally bilaterally symmetric and the most common comorbid conditions are atopic dermatitis and acne vulgaris.5 The lesions disappearing entirely when wiped with 70% of isopropyl alcohol are characteristic feature of the disease.1–4 No serious medical treatment is required but it entirely causes cosmetic concerns.2,4 Our patient has had brown, dirty like papules for over 1 year and the lesions disappeared after rubbing with 70% of alcohol before the biopsy. On our patient there was also no familial characteristic. Diagnosis is usually established clinically or after rubbing with alcohol during biopsy.6 Histopathologically, it is diagnosed with emergence of atrophy in epidermis, hyperkeratosis, mild acanthosis and orthokeratosis in basal layer. Parakeratosis is not observed. With periodic acid schiff coloration, pityrosporum can be observed in stratum corneum.7 Acanthosis nigricans, confluent and reticular papillomatosis, pityriasis versicolor, dermatosis neglecta, seborrheic keratosis should be taken into consideration during differential diagnosis. When rubbed with isopropyl alcohol lesions disappear entirely, and generally do not recur. Treatment of the disease is effective, inexpensive and painless.7,8

We have decided to present this case due to the fact that it is a rare disease and it is easy to diagnose and treat. So, it should be avoided to do unnecessary tests and treatments. In patients who have pigmentation disorder, TFFD should be taken into consideration for differential diagnosis.