acanthosis nigricans terra firma-forme dermatosis

7/31/2019 Acanthosis Nigricans Terra Firma-Forme Dermatosis

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Terra firma-forme dermatosis revisitedJohn Browning MD, and Ted Rosen MDDermatology Online Journal 11 (2): 15

Baylor College of Medicine and Michael E. DeBakey Veterans Affairs Medical Center, Houston, Texas.

[email protected]

Terra firma-forme dermatosis is a cutaneous discoloration resembling dirt, hence the

clinical name. The dyschromia cannot be removed with routine soap and water washing, but

can be eliminated by rubbing with isopropyl alcohol. Although the condition poses no serious

medical threat, it is cosmetically distressing. Our experience is that this entity is much morefrequent that might be expected when considering the paucity of reports in the readily available

medical literature. We chronicle a series of cases to highlight occurrence in widely divergent

demographic groups and long duration of remission following appropriate topical intervention.

The cause remains unknown.

Introduction

Terra firma-forme dermatosis is a relatively recently described entity which, in our

experience, is much more common than might be expected when surveying the medical

literature [1, 2, 3, 4]. Although it poses no serious medical threat, it is quite cosmetically

distressing. Clinical recognition leads to prompt and simple therapy, thereby avoiding complexand costly evaluation. We herein document and illustrate six cases of this bizarre dermatosis

whose etiology remains uncertain.

Case Reports

Case 1

A 54-year-old healthy white male presented with a many-year history of an asymptomaticbrown rash on the trunk. The patient assured the examiners that he maintained good hygiene,

including daily showers with soap. Physical exam disclosed palpable, papillomatous brown

plaques on his back as well as his neck and periaxillary skin (Fig. 1). Areas of dark-brownhyperpigmentation could be completely rubbed off with isopropyl alcohol (Fig. 2). A 3.5-mm

punch biopsy from an affected area revealed prominent lamellar hyperkeratosis with focal areas

having compact orthokeratosis arranged in whorls (Figs. 3 and 4). Vigorous alcohol rubbing

removed virtually all of the pigmentation. The patient was lost to long-term followup.
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Figure 1 Figure 2

Figure 1. Extensive dirty dermatosis of the back

Figure 2. Note removal of dermatosis with isopropyl alcohol

Figure 3 Figure 3

Figure 3. Biopsy showing hyperkeratosis (hematoxylin-eosin

x 20)

Figure 4. Close up biopsy showing orthokeratotic whorls

(hematoxylin-eosin x 100)

Case 2

A 19-year-old white female college student complained of gradually increasing,

asymptomatic discoloration involving the neck and both arms. The patient was a fastidious

individual, showering once or twice daily. She was healthy and ingesting neither medicationsnor nutritional supplements. Physical examination disclosed subtle but clear-cut light-brown

hyperpigmentation involving both sides of the neck and the lateral aspect of both upper arms

(Fig. 5). The patient refused biopsy when it became obvious that all areas could be easilycleared by rubbing with isopropyl alcohol (Fig. 6). The patient remained free of dyschromia 2years following removal of all abnormal pigmentation with alcohol.
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Figure 5 Figure 6

Figure 5. Subtle pigmentation of arms

Figure 6. Removal of pigmentation by isopropyl alcohol

Case 3

A 72-year-old relatively healthy white male presented with a 1-year history of multiple

asymptomatic scalp lesions. The patient routinely cleansed his scalp with over-the-counter

shampoo at least three times weekly. Physical examination disclosed eight prominent,irregularly-shaped jet-black plaques scattered on the central and posterior scalp (Fig. 7). The

neck, torso, and arms were uninvolved. Differential diagnosis comprised primarily of tumors:

pigmented basal cell carcinoma, squamous cell carcinoma in situ, seborrheic keratosis, andmelanocytic neoplasia. However, several of the areas were easily and completely removed by

light rubbing with isopropyl alcohol, confirming the diagnosis of dirty dermatosis of the scalpv

(Fig. 8). All lesions were then removed in a similar manner, and the patient remains clear 3

years later.

Figure 7 Figure 8

Figure7. Dirty dermatosis of the scalp. Area rubbed with

alcohol within white square

Figure 8. After rubbing with alcohol, dyschromia removed

easily
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Case 4

A 9-year-old boy of Indian ancestry was brought by his mother for a second opinion. Shehad been told that her son had acanthosis nigricans due to the velvety-textured, dark

hyperpigmentation present on both sides of his neck for the past 6 months (Fig. 9)/ She wasfurther advised that no treatment was available. Extensive and expensive laboratory evaluationdetected no endocrine abnormalities. The area was easily normalized by lightly rubbing with

isopropyl alcohol (Fig. 10). The child remained free of pigmentation 6 months following

rigorous cleansing of all affected areas with alcohol.

Figure 9 Figure 10

Figure 9. Dirty dermatosis of the neck in 9-year-old boy

Figure 10. Note removal of discoloration by isopropyl alcohol

Case 5

A 27-year-old white female homemaker complained of apatch of discoloration on the front of the neck which could not

removed by soap and water (Fig. 11). She showered daily, had

no chronic illnesses and was ingesting no medication. Thesmall area cleared easily when swabbed with isopropyl

alcohol. She remains free of this annoyance over 26 years

later.

Case 6

A healthy 30 year-old white male sought dermatologicalconsultation regarding discoloration of the arms while

hospitalized for open fracture reductions following automotive trauma. He worked in an office

environment, showered once or twice daily, and was taking no medications. Physicalexamination disclosed dark-brown patches involving the middle third of the dorsal aspect of

Figure 11

Figure 11. Subtle patch of

discoloration in center of

neck
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both arms (Fig. 12). All areas were restored to normal by rubbing with isopropyl alcohol (Fig.

13). Phone follow up 1 year later revealed that the lesions had not returned.

Figure 12 Figure 13

Figure 12. Prominent pigmentation of the dorsal forearm

Figure 13. Note removal of pigmentation following isopropyl

alcohol rub

Discussion

Terra firma-forme dermatosis has likely afflicted mankind throughout the ages but wasonly first described in the medical literature in the twentieth 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 [1]. Terra firma-forme dermatosis ischaracterized by brown, dirt-like discoloration that cannot be removed by bathing with water or

rubbed off with routine detergent soap. It It has most often been seen in children [1,2,3,4] but

it has also been described in adults [1]. When involving children, it can be very distressing totheir parents who cannot obtain clean appearing skin with routine cleansers. Terra firma-forme

dermatosis most often involves the neck and trunk but has also been reported on the scalp [3]

and the pubic region [4]. Our case series graphically demonstrates the wide range of ages (ages9-72) and sites (neck, arm, back, axillary line, and scalp) that can be affected.

The cause of terra firma-forme dermatosis is unknown. At fist glance these patients mayappear to have confluent and reticulated papillomatosis (CARP) or acanthosis nigricans.

However, when biopsy is performed to clarify the diagnosis, the dirty dermatosis often wipes

off with the alcohol pad being used to prep the skin. In many cases, aggressive effort with

application of substantial shearing force is required to remove the brown pigmentation.Therefore, when this condition is suspected, firm, persistent pressure should be applied while

rubbing the skin with alcohol.

Histopathologic examination of terra firma-forme dermatosis reveals prominent lamellar

hyperkeratosis with focal areas having compact orthokeratosis in whorls; no parakeratosis is

seen. Duncan, Tschen, and Knox also performed additional histopathologic studies in theirinitial report; Fontana-Masson-stained sections showed increased melanin in the compact
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hyperkeratotic areas and the basal layer. Toluidine blue staining of plastic-embedded sections

showed numerous keratin globules throughout the thick stratum corneum. Periodic acid-Schiffstains demonstrated occasional yeast cells thought to be Pityrosporrum. Brown-Bren-stained

tissue sections showed only normally distributed bacteria [1].

For patients with extensive terra firma-forme dermatosis, educating the patient or theiraccompanying family member on how to clean their skin at home using isopropyl alcohol will

save an extensive amount of time from performing the same service in the clinic. In ourexperience, recrudescence is exceptionally rare, even though individuals do not alter their

cutaneous habits or exogenous exposures in any way. In this case series, one patient had over

25 years of clearance and the others remained clear from 6 months to 3 years. In the uncommonevent of recurrence, once a week application of isopropyl alcohol will suffice as prophylaxis.

Conclusions

Awareness of terra firma-forme dermatosis facilitates prompt diagnosis and therebyprevents unnecessary biopsy and extensive endocrine evaluation. As illustrated by our case

series, this condition can affect both sexes, as well as youthful to geriatric individuals. While

the neck is a common site, terra firma-forme dermatosis can also appear on other body regions,from the extremities and torso to the scalp. It is very satisfying for both the patient and 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 apermanently disfiguring condition.

References

1. Duncan WC, Tschen JA, Knox JM. Terra firma-forme dermatosis.

Arch Dermatol. 1987 May;123(5):567-9.PubMed

2. O'Brien TJ, Hall AP. Terra firma-forme dermatosis. Terra firma-forme dermatosis.

Australas J Dermatol. 1997 Aug;38(3):163-4.PubMed

3. Mallari R, Sinclair RD. Terra firma-forme dermatosis of the scalp.

Br J Dermatol. 2002 Nov;147(5):1019.PubMed

4. Raveh T, Gilead LT, Wexler MR. Terra firma forme dermatosis.

Ann Plast Surg. 1997 Nov;39(5):542-5.PubMed

2005 Dermatology Online Journal
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