Дерматологи диагностируют у 45-летнего мужчины икhtiоз vulgaris на фоне сухости кожи

Slideshow - Slide A 45-year-old man presents with a 1-year history of progressively dry, rough skin involving the bilateral lower extremities. He reports associated mild pruritus that worsens during colder weather and after prolonged hot showers. The rash has not significantly improved despite regular use of over-the-counter emollients and moisturizers. He denies pain, blistering, drainage, or systemic symptoms. His medical history is otherwise unremarkable, and he denies a personal or family history of psoriasis, eczema, or autoimmune disease. On physical examination, there are fine polygonal brown-to-gray adherent scales over the bilateral shins with background xerosis (Figure). The flexural surfaces are relatively spared. There is no erythema, fissuring, or evidence of secondary infection. The remainder of the skin examination is unremarkable. Ichthyosis vulgaris is a common disorder of keratinization characterized by dry, thick skin that resembles fish scales. It affects 1 in 100 to 250 individuals and presents in infancy or early childhood. The condition arises from loss-of-function variants in the... Submit your diagnosis to see full explanation. Ichthyosis vulgaris is a common disorder of keratinization characterized by dry, thick skin that resembles fish scales. It affects 1 in 100 to 250 individuals and presents in infancy or early childhood. The condition arises from loss-of-function variants in the filaggrin gene. Inherited in an autosomal semi-dominant fashion, these mutations result in a deficiency of the filaggrin precursor profilaggrin, a key component of keratohyalin granules found in the stratum granulosum. This impairs the aggregation of keratin filaments, which compromises the integrity of the epidermal barrier. The lack of filaggrin reduces the production of water-retaining amino acids (eg, histidine) that moisturize the skin. Together, these defects manifest as the clinical features of ichthyosis vulgaris and lend to its association with other cutaneous disorders such as keratosis pilaris and atopic dermatitis.1,2 The xerotic scales of ichthyosis vulgaris typically affect the trunk and extremities. Flexor surfaces are usually spared because increased humidity acts as a protective factor. The scales are white, light gray, or brown in color. On the lower legs, the scales are larger and centrally adherent. Involvement of the palms and soles demonstrates hyperlinearity.1,2 The disease burden of ichthyosis vulgaris depends on both genetic and environmental factors. Patients with heterozygous mutations have a milder presentation, while those with homozygous mutations have more severe symptoms including peeling, a more widespread distribution, and painful palmoplantar fissures. The condition improves in warm, sunny weather and higher humidity and worsens in dry, cold climates.1 Although ichthyosis vulgaris is a clinical diagnosis, additional studies can provide diagnostic support. On histopathology, mild orthokeratotic hyperkeratosis can be observed along with a normal, reduced, or undetectable stratum granulosum. Keratohyalin granules may be absent or smaller in size on electron microscopy. Notably, an inflammatory infiltrate is not present. Immunohistochemistry will reveal scant or negative staining for filaggrin.1,2 An important differential diagnosis to consider for ichthyosis vulgaris is acquired ichthyosis. They share clinical and histologic features, but acquired ichthyosis tends to present later in life, coinciding with certain conditions, medications, and chemical exposures. Reported conditions include malnutrition, infection (eg, with human T-lymphotropic virus), paraneoplasms (eg, Hodgkin and non-Hodgkin lymphoma), inflammatory disorders (eg, autoimmune thyroiditis), and metabolic disorders (eg, diabetes).3 Patients presenting with what appears to be ichthyosis vulgaris who do not have a childhood history of the disorder require a more extensive workup to rule out occult malignancy and other inciting factors. Of note, because the patient in this case was unsure of a childhood history of similar cutaneous findings and reported worsening of his xerosis in the past year, a workup for underlying etiologies was performed and was negative. Ichthyosis vulgaris usually improves with age. For cases that require treatment, the primary goal is disease management with emollients, keratolytic agents, and humectants. Agents with demonstrated efficacy include urea; glycolic, lactic, or salicylic acid; and propylene glycol. Retinoids are not typically indicated for ichthyosis vulgaris except for trifarotene, which was granted Orphan Drug Designation by the FDA for treating congenital ichthyoses.1,2 Audrey Nguyen, BS, is a medical student at Baylor College of Medicine in Houston, Texas. Anna Catinis, MD, is a dermatology resident at the Baylor College of Medicine. References - Bolognia JL, Schaffer JV, Cerroni L. Dermatology. 5th ed. Elsevier Ltd; 2025. - Jaffar H, Shakir Z, Kumar G, Ali IF. Ichthyosis vulgaris: an updated review. Skin Health Dis. 2022;3(1):e187. doi:10.1002/ski2.187. - Park JS, Saeidian AH, Youssefian L, Hsu S, Vahidnezhad H, Uitto J. Acquired ichthyosis, asteatotic dermatitis or xerosis? An update on pathoetiology and drug-induced associations. J Eur Acad Dermatol Venereol. 2023;37(1):47-56. doi:10.1111/jdv.18608.