Abstract

Davener’s dermatosis is a variant of frictional hyperpigmentation first reported in 2000. It appears clinically as an elongated, vertical, midline, hyper pigmented patch with ill-defined borders, distributed along the skin over bony prominences of inferior thoracic and lumbar vertebrae. Histopathology revealed diffuse hyperkeratosis and hyperplastic epidermis with diffuse basal hypermelanosis. We report a case of Davener’s dermatosis in a male student, though common which is not widely reported in literature which was treated with 1064-nm Q-switched Nd: YAG laser with low fluence with partial improvement.

Keywords: Frictional hypermelanosis; Davener’s dermatosis.

Citation: Rajagopalan R. Davener’s dermatosis: A case report. J Clin Images Med Case Rep. 2023; 4(11): 2699.

Introduction

Davener’s dermatosis is an uncommon variant of benign frictional melanosis first described in 2000 by Naimer et al. [1] when he analysed 13 male full time students at Orthodox Jewish Talmudic seminaries (Yeshivas). It consisted of an elongated, vertical, midline, hyper pigmented patch with undefined borders, which was distributed along the bony skin prominences of the lower thoracic and lumbar vertebrae. Predominant among skin prototypes III-V. Clinical condition was often not recognized by them. Mean body mass index was lower than the general population. Histopathological features include a marked diffuse hyperkeratosis and hyperplastic epidermis with diffuse hyperpigmentation. The phenomenon can be attributed to friction from the firm backrests against the skin surface of the lower back generated by the characteristic swaying activity that traditionally accompanies Torah study or “davening” (praying) and termed it Davener’s dermatosis. Even though treatments are ineffective unless the incriminating cause (friction) is eliminated or reduced, there are reports of treatment with 1064-nm Q-switched Nd: YAG laser with low fluence [2].

Case report

A 22-year-old engineering student with scalp psoriasis on regular treatment with lean body structure who is otherwise healthy presented with 4-year-old history of black patches with indistinct borders over lower back. He is asymptomatic apart from occasional scalp pruritus. He had no relevant family or medical history. He spent most of his time sitting in a wooden chair, browsing the mobile or computer, constantly rubbing his back on rigid chair. No history of using nylon loofah or coconut husk during bathing. On physical examination, there were large dry scales in scalp and diffuse hypermelanotic patches with ill-defined margins over protuberant spine processes of lower thoracic and upper lumbar vertebrae. Rest of skin examination was unremarkable except for minimal scalp psoriasis. We made a diagnosis of benign frictional melanosis due to mechanical trauma (swaying activity). We proceeded with treatment after a punch skin biopsy to rule out frictional amyloidosis. It showed epidermal hyperplasia and diffuse hyperpigmentation of stratum basale with no dermal amyloid deposits. We treated him with 1064-nm Q-switched Nd: YAG laser with low fluence with insignificant improvement after 3 sittings. Patient then refused further treatment citing only partial resolution. He was prescribed moisturisers for local use and to use soft cushion as back rest and to change the chair as completely foam padded.

Figure 1: Hyper pigmented patches over the lower back in the midline above the bony protuberances.

Figure 2: Epidermal hyperplasia, diffuse hyperkeratosis, basal pigmentation.

Discussion

Davener’s dermatosis is an uncommon variant of benign local friction hypermelanosis [3,4]. These skin discoloration are reportedly seen in prayer rituals and ceremonies [5]. Physical stresses such as friction, trauma or chronic irritation are often found on analysis. Mostly seen on bony prominences on back in skin types III-V. Clinically two types exist- cobblestone and continuous. It is characterised by longitudinal hyper pigmented patches on skin over spinous processes of lower back due to repeated rubbing over rigid back rest. The characteristic histopathological changes include diffuse hyperkeratosis, acanthosis, clubbing and fusion of rete ridges and basal epidermal hyperpigmentation. Repeated mechanical rubbing lead to cutaneous hyperkeratosis and pigmentation [6]. With no effective treatment except removal of triggering factors, Nd; YAG laser / Chemical peels like Glycolic Acid (GA); Trichloroacetic Acid (TCA) can be tried [2,7].

Conclusion

Davener’s dermatosis is a form of benign friction hypermelanosis with network of brown or black pigmentation over skin of spinous processes. There is no age, gender or racial predilection and it can be noticed on any part of the body. The mechanism is thought to consist of migration of melanosomes into the dermis due to mechanical stimulation and inflammatory changes, resulting accumulation of melanophages in dermis in the friction prone area. Treatment is usually conservative. If detected early, stopping the friction may clear discolouration over months or years. New therapeutic modalities like focal chemical peels/low fluence Nd: YAG laser. This report highlights the importance of a thorough history in patients presenting with pigmented lesions and to rule out other causes.

References

1. Naimer SA, Trattner A, Biton A, Avinoach I, Vardy D. Davener’s dermatosis: a variant of friction hypermelanosis. J Am Acad Dermatol. 2000; 42: 442-5.
2. Cho S, Lee SJ, Lee JH, Cho SB. Treatment of Davener’s dermatosis using a 1064-nm Q-switched Nd: YAG laser with low fluence. International Journal of Dermatology. 2012; 51: 1394-1396.
3. Friction hypermelanosis: Other variants. Magaña, Mario et al. Journal of the American Academy of Dermatology. 2002; 47: 454.
4. Goodheart HP. Devotional dermatoses: A new nosologic entity? J Am Acad Dermatol. 2001; 44: 543.
5. Al-Aboosi M, Abalkhail A, Kasim O, et al. Friction melanosis: A clinical, histologic, and ultrastructural study in Jordanian patients. Int J Dermatol. 2004; 43: 261-4.
6. Khoo ZX, Chong JH, Koh MJA. Davener’s dermatosis Archives of Disease in Childhood. 2019; 104: 1137.
7. Sacchidanand S, Shetty AB, Leelavathy B. Efficacy of 15% trichloroacetic Acid and 50% glycolic Acid peel in the treatment of frictional melanosis: A comparative study. J Cutan Aesthet Surg. 2015; 8: 37-41.