Acquired ichthyosis is a non-hereditary skin condition characterised by dry and rough skin with scaling. It is often described as “fish scale skin” and usually appears for the first time in early adult life.
Acquired ichthyosis may be associated with internal diseases or with the use of certain medications. There is no known gender or racial predilection in developing this condition.
The severity of the condition differs from person to person.
There are three main groups of causes of acquired ichthyosis:
- Ichthyosis associated with cancers
The most common cancer associated with acquired ichthyosis is Hodgkin’s disease (a lymphoma). The skin changes may occur prior to, during and post treatment of the lymphoma. These changes usually occur on limbs or trunk. Often the lesions improve with treatment but may recur if there is a relapse.
Other cancers associated with the condition include: non-Hodgkin’s lymphoma; cutaneous T cell lymphoma; lymphomatoid papulosis; multiple myeloma; breast, lung, cervical and liver cancers; and sarcomas.
- Ichthyosis and other diseases
Acquired ichthyosis can be caused by malnutrition or health conditions that reduce lipid (fat) and vitamin absorption (e.g. Crohn’s disease, coeliac disease). Other conditions such as chronic liver disease, kidney failure, thyroid and parathyroid diseases, sarcoidosis, leprosy, bone marrow related conditions and rarely autoimmune connective tissue diseases (e.g. lupus, dermatomyositis) may also cause ichthyosis. Individuals affected with AIDS have also been reported as developing ichthyosis as well.
- Drug-induced ichthyosis
Certain medications have been reported to cause ichthyosis. These include cholesterol lowering agents (e.g. triparanol, nicotinic acid), targeted cancer therapy (e.g. BRAF inhibitors, EGFR inhibitors), allopurinol and many more.
Acquired ichthyosis looks like dry small fine scales similar to fish scales which are often lifted up at the edges. The colour differs from white, brown to grey. The severity of the condition varies from barely visible lesions to strong horny plates.
Lesions are most often seen on knees and elbows but can also be seen on the trunk. The face and body folds are rarely affected.
Individuals who have a severe form of ichthyosis may develop infection from cracks and splits on the skin. Impaired hearing and/or impaired eyesight may result from the build-up of scales in ears and eyes. Dry and cracked skin may be painful and prone to bleeding. Movement of certain parts of the body may be limited because of pain.
Acquired ichthyosis is often diagnosed clinically from a medical history and skin examination. When in doubt, a skin biopsy may be needed to support the diagnosis.
The main goal of the treatment is to hydrate the skin and to prevent complications such as infection.
Use of soap-free cleansers and regular moisturisers are essential. Moisturiser additives (such as urea, lactic acid, salicylic acid or alpha hydroxy acid) help to reduce the scale. Soaking in a bath with salt or very diluted bleached water can reduce the risk of secondary infection. However, oral antibiotics are often needed to manage infections. Severe cases may benefit from topical or oral vitamin A based medications called retinoids.
Acquired ichthyosis tends to improve when the underlying health condition is treated or the causative drug is stopped.
This information has been written by Dr Shelley Ji Eun Hwang & A/Professor Pablo Fernandez-Penas
