|Year : 2019 | Volume
| Issue : 3 | Page : 176-177
Alopecia totalis sparing congenital melanocytic nevus: Renbök phenomenon
Toshiyuki Yamamoto1, Hideko Okabe2, Michiko Hoshi2
1 Department of Dermatology, Fukushima Medical University, Fukushima, Japan
2 Dermatology Clinic, Hoshi General Hospital, Koriyama, Japan
|Date of Web Publication||24-May-2019|
Prof. Toshiyuki Yamamoto
Department of Dermatology, Fukushima Medical University, Hikarigaoka 1, Fukushima 960-1295
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Yamamoto T, Okabe H, Hoshi M. Alopecia totalis sparing congenital melanocytic nevus: Renbök phenomenon. Dermatol Sin 2019;37:176-7
The Renbök phenomenon (reverse or inverse Köbner phenomenon) was first described by Happle et al. They reported four cases with alopecia areata and concomitant psoriasis or seborrheic dermatitis of the scalp, in which the lesions of these inflammatory skin diseases matched with unaffected areas by alopecia. Herein, we report a case in which alopecia involved the entire scalp, sparing a congenital melanocytic nevus.
A 40-year-old female was referred to our hospital, for the treatment of diffuse alopecia of the scalp. She developed alopecia areata on the parietal scalp 6 years previously, which once improved by treatment with topical corticosteroid (betamethasone butyrate propionate) and carpronium chloride solution; however, 5 years later, her alopecia relapsed, and the affected areas were enlarged. Before the referral, she was treated with excimer light therapy and methylprednisolone pulse therapy at another hospital, which, however, were not effective. After obtaining informed consent, topical application of squaric acid dibutylester (SADBE) solution was started with an initial concentration of 0.001%. Six months later, due to a move, she was referred to our hospital for the continuation of the treatment. Physical examination revealed total alopecia on the scalp, but normal hair growth was observed in the congenital melanocytic nevus [Figure 1]. Neither eyebrows nor eyelashes were involved. Laboratory examination showed normal liver and renal function. Anti-nuclear antibody was negative, and thyroid disease was denied. She is currently treated with 0.01% SADBE by which hair growth is observed in the occipital region.
To date, only several cases exhibiting the Renbök phenomenon have been reported in overlapping inflammatory diseases,,,,, which have shown that some inflammatory processes such as alopecia is inhibited by psoriasis, or alopecia prevented the induction of psoriasis. Thereafter, this term was extended to include conditions with the mosaic phenomenon. The mechanism is explained by the interaction between different conditions mediated by Th1, Th2, and Th17 cells between psoriasis and alopecia, which exert exclusive effects mutually. In the present case, alopecia diffusely and totally involved the scalp, sparing a hairy melanocytic nevus. To date, a few similar cases have been reported.,, The first case was a 13-year-old girl with universal alopecia, including the eyebrows and lashes, who developed an alopecia-resistant pigmented congenital nevocellular nevus on the scalp. In the second case, alopecia areata spared a congenital melanocytic nevus on the eyebrow of a 16-year-old boy. The third case was a 30-year-old man with alopecia areata universalis, which spared a large nevus flammeus on the left parietal scalp. These cases may suggest that a congenital nevus is genetically unsusceptible to alopecia. The phenomenon is explained by genetic mosaicism, which reflects a distinct microenvironment and may protect a hairy congenital nevus from hair loss. This is contrary to the immunologic phenomenon seen in the halo nevus, in which depigmentation surrounding the melanocytic nevus is induced by infiltrating T-cells. Further studies of the mechanism in which congenital melanocytic nevus escapes from the local immune control of alopecia are necessary.
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.
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Conflicts of interest
There are no conflicts of interest.
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