Ichthyosis

Ichthyosis is a group of rare skin conditions that cause dry, scaly skin resembling fish scales. Most types are inherited and present from birth, though the condition can occasionally develop later in life.

Table of contents

• What is ichthyosis?
• Symptoms
• Causes and types
• Diagnosis
• Treatment options
• Managing ichthyosis at home

What is ichthyosis?

Ichthyosis is a group of rare skin disorders characterized by very dry, scaly skin. The name comes from the Greek word “ichthys,” meaning fish, because the skin can resemble fish scales in appearance^[1]. There are more than 20 different types of ichthyosis, ranging from mild to severe^[1].

The condition affects how the skin renews itself. In normal skin, new cells form in the deepest layer while dead cells shed from the surface at a balanced rate. In ichthyosis, either dead cells shed too slowly, causing a buildup of dry, scaly layers, or new cells are produced too slowly, allowing too much moisture to be lost from the skin^[5].

Ichthyosis vulgaris is by far the most common form, accounting for more than 95% of cases. It affects approximately 1 in every 250 people^[2]. Most people with this type have mild symptoms that may even be confused with ordinary dry skin.

Symptoms

The main symptom of ichthyosis is very dry, scaly skin that may also be thick and rough. It usually affects large areas of the body including the arms, legs, torso, ears, face, or even the whole body^[1].

The skin may look or feel bumpy, chapped, cracked, dry, itchy, rough, thick, or scaly. White, gray, or brown scales commonly appear on the front of the legs, back of the arms, scalp, back, or stomach. Sometimes the edges of scales curl, making the skin feel particularly rough^[2].

The symptoms are often present from birth, but they can also appear after a few months or years. In most children with ichthyosis, symptoms usually appear by the age of five years^[5]. The symptoms of ichthyosis often worsen in winter months and improve during summer^[2].

In more severe cases, ichthyosis can cause additional symptoms including blistered skin, a thin yellow shiny layer on the skin at birth that dries out and flakes off, hair loss, tight skin which can make moving the affected area painful, skin infections, reduced sweating which can lead to overheating, and problems with hearing or eyesight^[1].

Most children with ichthyosis will have a mild form of the disease with minimal effect on their general health and wellbeing. Some children may find the condition uncomfortable or embarrassing. In rare cases, it can be very severe and affect the entire skin surface or cause blisters, leading to repeated infections, discomfort, and sweating problems^[5].

Causes and types

Most types of ichthyosis are inherited, meaning they are passed down from parents through genes. These genetic forms are usually present at birth or appear soon after. The condition is caused by mutations in genes that code for proteins needed to maintain the skin’s protective barrier^[5].

Ichthyosis vulgaris is the most common type. It usually appears between 3 and 12 months of age with fine scales and varying degrees of skin dryness. Scaling is most prominent on the trunk, abdomen, buttocks, and legs, while areas like the inner elbows and knees are typically spared^[4]. This type is caused by mutations in the gene that codes for filaggrin, a protein that helps bind skin cells together to form the protective skin barrier^[2].

X-linked ichthyosis is the second most common form, affecting approximately 1 in 6,000 males. It appears in the first few months of life and affects almost exclusively boys. It is characterized by dark scales forming large flakes mainly on the arms and legs. This type is caused by lower levels of an enzyme called steroid sulfatase^[3].

Autosomal recessive congenital ichthyosis includes several rarer types such as lamellar ichthyosis and congenital ichthyosiform erythroderma. These tend to have more severe symptoms and may affect the entire body^[1].

Harlequin ichthyosis is the most severe but also the rarest form. It affects approximately 1 in 1 million children and is characterized by thick scaly plates all over the skin that can affect the appearance of a newborn’s face and limit joint movement^[6].

Ichthyosis can also develop later in life as an acquired condition. This form typically appears in adulthood and may be linked to other health conditions such as cancer (particularly lymphoma), kidney failure, HIV, lupus, or sarcoidosis. It can also result from certain medications^[2].

As a genetic disorder, inherited ichthyosis is not caused by infection and is not contagious—it cannot be caught from others^[5].

Diagnosis

A doctor, often a specialist in skin conditions called a dermatologist, can usually diagnose ichthyosis by examining the skin and discussing symptoms. If you or your child have symptoms of ichthyosis, you should see your doctor, who may refer you to a skin specialist^[1].

The specialist will examine the skin and ask what makes the symptoms better or worse. They will also ask about family history of skin conditions and any medications being taken^[2].

Ichthyosis is usually diagnosed based on clinical examination and does not require testing. However, in some cases, additional tests may be performed. A skin biopsy may be done, where a small sample of skin is removed and examined under a microscope. A blood test or saliva test may be ordered to look for genetic mutations, such as those affecting filaggrin production^[2].

Ichthyosis vulgaris can be difficult to diagnose because many people with mild cases assume they simply have dry skin. If regular moisturizers do not help improve the condition, it may be ichthyosis vulgaris^[2].

Treatment options

Most types of ichthyosis cannot be cured, but treatments are available to help manage the symptoms^[1]. A skin specialist will discuss the different treatment options available.

The primary treatments include moisturizing treatments, also called emollients, such as lotions, creams, ointments, and bath oils. These should be applied to affected skin at least once a day, ideally when the skin is still wet after bathing or showering^[1]. Moisturizers that contain petroleum jelly, mineral oil, salicylic or lactic acid, ammonium lactate, ceramides, dexpanthenol, or urea are particularly helpful^[8].

Peeling creams, also known as keratolytics, help to loosen the scales on the skin and encourage them to come off. Examples include creams containing lactic acid, salicylic acid, ammonium lactate, hydroxy acids, or urea. Unfortunately, these can sometimes be irritating, causing redness, stinging, itching, or discomfort. The strength of the cream can be adjusted if these symptoms occur^[5].

For more severe ichthyosis symptoms, treatment may also include antibiotics to treat or prevent skin infections, and retinoid tablets or creams to help improve the appearance of scaly skin. Retinoids are substances related to vitamin A that help the skin shed excessive scales^[1]. However, taking high doses of vitamin A can cause side effects including dry eyes, lips, and nose, as well as nosebleeds, headaches, nausea, and high blood cholesterol. Retinoids can only be prescribed by dermatologists and require strict monitoring with regular check-ups and blood tests^[5].

If ichthyosis symptoms are caused by another health condition or medicine, treating that condition or changing the medicine can improve the symptoms^[1].

Managing ichthyosis at home

There are several things you can do at home to help ease ichthyosis symptoms. Use emollients on affected skin at least once a day, ideally when the skin is still wet after bathing or showering. Try different types of emollient to find one that works best for you^[1].

Use a comb on wet hair to remove scaly skin on the scalp. Do not use soap on affected skin—use an emollient instead of soap. It is also important to avoid smoking or going near flames if using an emollient that contains paraffin^[1].

Moisturizers help improve skin dryness by replacing lost moisture and holding it in the skin. They need to be applied regularly, particularly after showering or bathing^[5]. Regular moisturizing, combined with gentle exfoliation to remove dead skin cells, forms the foundation of home care.

If you or your child has ichthyosis, you may need to spend time each day caring for the skin. Symptoms are often worse in winter months and in dry climates, because warmth and humidity can improve these symptoms^[4].

Talk to your skin specialist if any treatments cause irritation, as adjustments can often be made to improve comfort while still managing the condition effectively^[1].