|Year : 2015 | Volume
| Issue : 2 | Page : 147-149
Localized Dowling-Degos disease
Bhushan Malhari Warpe
Department of Pathology, Grant Government Medical College and Sir JJ Group of Hospitals, Mumbai, Maharashtra, India
|Date of Web Publication||21-Nov-2015|
Bhushan Malhari Warpe
Grant Government Medical College and Sir JJ Group of Hospitals, Mumbai - 400 008, Maharashtra
Source of Support: None, Conflict of Interest: None
A 26-year-old young man came with complaints of abnormally dark skin coloring, particularly in the back of the hands and intertriginous folds between digits, progressively spreading in the last 5 years. There was no family history of the same. He had no personal and family history of skin disease or diabetes mellitus. A clinical diagnosis of drug-induced hyperpigmentation disorder was made. A skin biopsy of 0.3 cm × 0.3 cm which was totally embedded for histopathology reporting was obtained. The section revealed epidermis, dermis, and subcutaneous tissue. Epidermis shows hyperkeratosis, irregular acanthosis with focal filliform down growth of the epidermis. Multiple keratin horn cysts were seen in the down growth. The tips of rete ridges showed pronounced hyperpigmentation. The histopathological impression was Dowling-Degos disease (DDD). DDD is a rare genetic skin condition without a definite cure, although its prevalence is unknown. We report a DDD case in a young man.
Keywords: Dowling-Degos disease, genetic, family history
|How to cite this article:|
Warpe BM. Localized Dowling-Degos disease. Afr J Med Health Sci 2015;14:147-9
| Introduction|| |
Dowling-Degos disease (DDD) is a rare genetic skin condition, with unknown prevalence. Dark dot disease, DDD, Dowling-Degos-Kitamura disease, reticular pigment anomaly of flexures and reticulate acropigmentation of Kitamura are other names used for it. DDD and its variants can either be inherited from one parent (autosomal dominant) or appears without a family history (sporadic). ,,, The onset of classic DDD is in adult life, most commonly in the 20 s or 30 s but sometimes later. It slowly becomes more extensive with time, but not life threatening. DDD only affects the skin, and there are no internal effects. Skin affected by DDD can be itchy, especially in summer when the effects of heat, perspiration and friction aggravate the pigmentation and itch. Blistering is not a feature of this disease. ,
DDD is a skin condition characterized by a lacy or net-like (reticulate) pattern of abnormal hyperpigmentation, particularly in the body's folds and creases. These skin changes typically first appear in the armpits and groin area and can later spread to other skin folds such as the crook of the elbow and back of the knee. Less commonly, pigmentation changes can also occur on the wrist, back of the hand, face, scalp, scrotum (in males), and vulva (in females). ,
In our case, the back of hands and intertriginous areas between digits was the sites of localized skin involvement with hyperpigmentation.
| Case report|| |
A 26-year-old young man came with complaints of a progressive abnormally dark skin coloring, particularly in the back of the hands and intertriginous folds between digits of 5 years duration. He did not have any family history of the same or of diabetes mellitus. It was not associated with skin irritation and itchiness. He had no sexually transmitted infection. He was diagnosed with medication-induced hyperpigmentation disorder.
A skin biopsy of 0.3 cm × 0.3 cm which was totally embedded was obtained for histopathological analysis. The section revealed epidermis, dermis, and subcutaneous tissue. Epidermis shows hyperkeratosis, irregular acanthosis with focal filiform down the growth of epidermis. Multiple keratin horn cysts were seen in the down growth. Thin epithelial strands extend into the superficial dermis from the epidermis and hair follicles resulting in an "antler-like" pattern. The tips of rete ridges showed pronounced hyperpigmentation. Dermal perivascular lymphohistiocytic infiltrate is seen. The histopathological impression was given as DDD [Figure 1].
|Figure 1: (a) (Left): Photomicrograph - Multiple keratin horn cysts (arrow) were seen in the downgrowth of epidermis. The tips of rete ridges showed pronounced hyperpigmentation (H and E, ×400). Inset shows gross picture showing hyperpigmentation in the back of the hands and intertriginous folds between digits. (b) (Right) Photomicrograph - Epidermis shows hyperkeratosis, irregular acanthosis with focal filiform downgrowth of epidermis (arrow) (H and E, ×100).|
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The routine blood investigations revealed normal complete blood count and peripheral blood smear findings with hemoglobin-13 g/dl, total white cell count-6700/cu mm. Furthermore fasting blood sugar of the patient was 82 mg/dl.
| Discussion|| |
Dowling and Freudenthal  first delineated this genodermatosis as a distinct entity in 1938. In 1954, Degos and Ossipowski  described a patient with a similar case. Few patients with reticulate pigmented anomaly, also known as DDD, have been reported.
DDD is a rare condition affecting both sexes, but more common in females. DDD tends to develop early in adult life, with the onset of pigmentation occurring in individuals before they are aged 24 years. The flexural pigmentation has its onset from childhood to adult life. It may be intense, with a brownish black color and sometimes steel blue or navy overtones. However, if the condition is less severe, it is stippled in shades of brown. No verrucous or velvety papillomatosis is present, as might be seen in acanthosis nigricans. ,
DDD is characterized by flexural pigmented reticulate macules and sometimes comedo-like papules on the back and/or the neck (dark dot follicles). Some patients have pitted perioral scars. Pruritus of affected flexural areas may be the only symptom. In both male and female patients, pigmented reticulate macules may also be evident on the genitalia, where they may be seen alone. The pigmented eruption on the male external genitalia may be a cutaneous marker of underlying testicular carcinoma,  although the association is probably fortuitous. Bilateral nephroblastoma in familial Hay-Wells syndrome has been associated with familial reticulate pigmentation of the skin,  another possibly fortuitous association.
Typical clinical DDD may histopathologically be Galli-Galli disease.  Galli-Galli disease is a rare genodermatosis in the spectrum of reticulate hyperpigmentation, probably best regarded as an acantholytic variant of DDD. In Galli-Galli disease apart from histopathologic findings of DDD, we also get suprabasal epidermis showing nondyskeratotic acantholysis. The latter was not seen in our case.
DDD is often familial and appears to be inherited in an autosomal dominant manner.  A gene locus believed responsible in one Chinese patient was mapped to 17p13.3.  A genome-wide linkage analysis of two German families mapped this disease to 12q.  This region includes the keratin gene cluster, which was screened for mutations.
Loss-of-function mutations were identified in the keratin 5 (KRT5) gene in all affected family members and in six unrelated with DDD. Another study found the same KRT5 mutation in patients with reticulate pigmented anomaly and its acantholytic variant, Galli-Galli disease.  This variant has a genotype/phenotype correlation with mutations in the KRT5 gene.
Differential diagnoses include Hay-Wells syndrome, seborrhoeic keratosis, and Galli-Galli disease. The ectodermal familial abnormalities seen in Hay-Wells syndrome include skin, hair, teeth, nails, sweat glands, cranial-facial structure, and hands. Hence, we did not have Hay-Wells syndrome in our patient. Though clinically and histopathologically, DDD looks like Galli-Galli disease, but our case was not associated with suprabasal, nondyskeratotic acantholysis, which occurs in the later. Since only the top layers of the epidermis are involved, seborrheic keratoses are often described as having a "pasted on" appearance, unlike our case which had epidermal down growth too.
No treatment is effective for DDD. Topical retinoic acids, topical steroids, hydroquinone, tretinoin, and systemic retinoids have been used without success. DDD has been successfully treated with the fractional Er:YAG laser. The patient and his or her family should be educated about the common autosomal dominant nature of DDD. 
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Conflicts of interest
There are no conflicts of interest.
| References|| |
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