Dyschromatosis Symmetrica Hereditaria
Dyschromatosis symmetrica hereditaria (DSH), also described in the literature as reticulate acropigmentation of Dohi, is an autosomal dominant inherited pigmentary disorder. At the molecular level, DSH is caused by loss-of-function mutations in the ADAR gene (which encodes the enzyme adenosine deaminase acting on RNA 1) on chromosome 1q21. This enzyme is central to post-transcriptional RNA editing: it converts adenosine to inosine (A-to-I RNA editing) in the body’s own double-stranded RNA (dsRNA) molecules.
When ADAR is mutated, unedited dsRNA builds up in the cytoplasm and mistakenly activates innate immune sensors inside the cell (such as MDA5 and RIG-I). This misfiring sets off an autoinflammatory cytokine cascade, especially type I interferon, placing the epidermal melanin unit under acute biological stress. Under environmental triggers such as UV light, some melanocytes are damaged and die early, producing pale spots, while neighboring cells respond by making extra melanin. The result is a symmetric, net-like mix of dark and light spots on the backs of the hands and feet.
At Haute-Derma, we approach DSH with a carefully balanced, two-sided clinical strategy. Because too much and too little pigment sit side by side on the same small area of acral skin, DSH is a real challenge for conventional light-based treatments. We avoid high-energy photothermal methods that can trigger rebound pigmentation and instead use purely photomechanical picosecond laser to clear dark spots, combined with epidermal immune modulation to help repigment the white, melanocyte-depleted spots.
Our Specialist Approach to Managing DSH
Because DSH combines two opposite pigment changes confined to the hands and feet, Haute-Derma follows standardized treatment principles:
- Treating both pigment extremes together: A dual-action plan selectively breaks down excess melanin in the brown spots while protecting healthy melanocytes and encouraging them to migrate into the white spots.
- Avoiding cumulative heat: Only ultra-short-pulse lasers are used, so heat does not spread to surrounding tissue and trigger the interferon pathway that leads to post-inflammatory hyperpigmentation (PIH).
- Photoprotection for vulnerable cells: Strict control of UV exposure, which directly increases the load of unedited dsRNA inside the cells of people with DSH.
Assessment and Clinical Grading at Haute-Derma
To map out the most precise treatment plan, we carry out a thorough microscopic and molecular assessment:
- High-resolution dermoscopy of the pigment network: Under dermoscopy, the dark spots show a dense, tightly woven pigment network, evenly interspersed with sharply defined, droplet-shaped pale dots, creating the “marbled network” typical of Dohi’s disease.
- Histopathology of the epidermis: Biopsies of the brown spots confirm excess melanin in the basal layer; the white spots show a complete absence of pigment granules and melanocytes, with mild vacuolar change at the dermoepidermal junction.
- Next-generation sequencing (NGS) to identify the ADAR mutation: All coding exons of ADAR are analyzed to pinpoint the exact variant (point mutation, frameshift or protein-truncating change), confirming the diagnosis at the molecular level.
- Differential diagnosis from other reticulate pigmentary syndromes: Clinical analysis rules out look-alike conditions such as dyschromatosis universalis hereditaria (DUH), reticulate acropigmentation of Kitamura (RAK) and Dowling-Degos disease.
Clinical Management and Cosmetic Treatment at Haute-Derma
Our treatment strategy aims to restore a more even skin tone on the hands and feet:
- Picosecond laser (755 nm / 1064 nm) for dark spots: Picosecond lasers fire pulses lasting trillionths of a second, creating a mechanical (photoacoustic) shock wave. The peak energy shatters the macromelanosomes in the brown spots into tiny particles that macrophages clear easily, fading the spots safely without heat damage to the basement membrane.
- Fractional thulium laser (1927 nm) to encourage melanocyte migration: The laser creates microscopic treatment zones in the superficial epidermis. The controlled healing response stimulates healthy melanocytes from normal skin or the edges of brown spots to migrate and extend their dendrites into the pale spots.
- Topical agents that calm cellular stress signals: Topical formulations containing ectoine, high-strength tranexamic acid and niacinamide strengthen the skin barrier and help reduce inflammation and pigment activation when the skin is exposed to sunlight.
- Dedicated sun protection for the hands and feet: A broad-spectrum, water-resistant mineral sunscreen with SPF 50+ and PPD 30+ is essential to give the backs of the hands and feet the best possible protection from UVA/UVB and high-energy visible (HEV) light.
