Ichthyosis
Persistently dry, thickened, scaly skin
Quick Facts
- Type: Inherited or acquired skin disorder
- Hallmark: Dry, fish-scale-like skin
- Most common form: Ichthyosis vulgaris
- Mainstay of care: Intensive moisturizing and exfoliation
Overview
Ichthyosis refers to a family of skin disorders in which the skin becomes dry, rough, and covered in scales. The name comes from the Greek word for fish, because the scaling can look like fish skin. The problem usually lies in how skin cells are produced and shed: cells may be made too quickly or the outermost layer may not flake off normally, so dead cells pile up and form scales.
Most cases are inherited and present from infancy or early childhood, with ichthyosis vulgaris being by far the most common type. Less often, ichthyosis develops later in life as a sign of another medical condition, in which case it is called acquired ichthyosis. While inherited ichthyosis is usually lifelong, daily skin care keeps most cases comfortable and well controlled.
Symptoms
Symptoms range from mild dryness to widespread thick scaling, depending on the type. Common features include:
- Dry, rough skin that feels tight
- Fine white, gray, or brown scales, often on the shins, back, and arms
- Flaky scalp
- Deep cracks in the skin, sometimes painful, especially on the soles
- Extra lines and creases on the palms
- Itching, which can be mild or bothersome
Scaling often worsens in cold, dry weather and improves in warm, humid conditions. The folds of the elbows and knees are frequently spared in ichthyosis vulgaris.
Causes
Ichthyosis develops when the normal cycle of skin cell turnover and shedding is disrupted.
- Inherited ichthyosis: Caused by changes in genes that control the skin barrier and shedding. Ichthyosis vulgaris is linked to changes in the gene for filaggrin, a protein that helps the skin hold moisture and stay smooth.
- Acquired ichthyosis: Appears in adulthood and can be associated with thyroid disease, kidney disease, certain cancers such as lymphoma, HIV infection, nutritional problems, or some medications.
Because filaggrin is also involved in atopic dermatitis (eczema), people with ichthyosis vulgaris often have eczema, hay fever, or asthma as well.
Risk Factors
- A family history of ichthyosis or very dry skin
- Personal or family history of eczema, asthma, or hay fever
- Cold, dry climates and low indoor humidity
- An underlying condition (for acquired ichthyosis), such as thyroid or kidney disease or lymphoma
Diagnosis
A doctor or dermatologist can usually recognize ichthyosis by examining the skin and asking about the pattern, timing, and family history. Additional steps may include:
- Skin biopsy: Removing a small sample to look at under a microscope when the diagnosis is unclear.
- Genetic testing: Sometimes used to identify the specific inherited type.
- Blood tests: Ordered when acquired ichthyosis is suspected, to check for thyroid, kidney, or other underlying conditions.
Treatment
There is no cure for inherited ichthyosis, but treatment keeps the skin soft and reduces scaling. The cornerstone is consistent skin care.
- Moisturizers: Thick creams and ointments applied generously, ideally right after bathing while the skin is damp.
- Exfoliating products: Creams containing urea, lactic acid, salicylic acid, or other alpha-hydroxy acids help loosen and remove scale.
- Gentle bathing: Soaking and lightly scrubbing with a washcloth or pumice to remove softened scale.
- Prescription retinoids: Oral or topical vitamin-A-based medicines for severe types, used under specialist supervision.
For acquired ichthyosis, treating the underlying condition usually improves the skin.
Self-Care and Prevention
- Apply moisturizer at least twice a day and after every bath or shower
- Use a humidifier at home, especially in winter
- Bathe in lukewarm water and avoid harsh soaps
- Pat skin dry rather than rubbing
- Treat cracks promptly to prevent infection
When to See a Doctor
See a doctor if dry, scaly skin is severe, spreads, or does not improve with regular moisturizing, or if scaling appears for the first time in adulthood, which can signal an underlying illness. Seek prompt care if cracked skin becomes red, swollen, warm, painful, or oozing, as these are signs of infection that may need antibiotics.
Frequently Asked Questions
Is ichthyosis contagious?
No. Ichthyosis is not an infection and cannot be passed from person to person by touch. Most forms are inherited, and the acquired form is linked to other internal conditions rather than to contagion.
Can ichthyosis be cured?
Inherited ichthyosis cannot be cured, but it can be well controlled with daily moisturizing and exfoliating skin care. Acquired ichthyosis often improves when the underlying medical condition causing it is treated.
What is the best moisturizer for ichthyosis?
Thick creams and ointments work better than thin lotions, and products containing urea, lactic acid, or salicylic acid help remove scale. Applying moisturizer right after bathing, while the skin is still damp, locks in the most moisture.
Why does ichthyosis get worse in winter?
Cold air and dry indoor heating pull moisture out of the skin, which makes scaling and cracking worse. Using a humidifier and moisturizing more often during winter usually helps.
Does ichthyosis appearing in adulthood mean something serious?
Scaling that begins for the first time in adulthood can be acquired ichthyosis, which is sometimes a sign of thyroid disease, kidney disease, certain cancers, or another condition. It is worth seeing a doctor so any underlying cause can be checked.
References
- American Academy of Dermatology. Ichthyosis vulgaris.
- National Institutes of Health, Genetic and Rare Diseases Information Center (GARD). Ichthyosis.
- MedlinePlus, U.S. National Library of Medicine. Ichthyosis vulgaris.
- DermNet. Ichthyosis.