Pityriasis rubra pilaris symptoms are orange-red scaly plaques, which are inflamed and sharply demarcated from normal skin. Pityriasis rubra pilaris is often abbreviated as PRP. Pityriasis rubra pilaris is a rare, chronic skin condition, the cause of which is unknown. The hereditary variant is attributed to a mutation in the gene for CARD14. The classic non-hereditary form of pityriasis rubra pilaris is the most common and is mainly seen in people over 50, but sometimes also in children. Depending on the clinical variant, it usually takes several years before remission occurs and the symptoms disappear. Treatment of this skin condition can consist of applying greasy ointments and creams and corticosteroids and possibly taking the drug Neotigason®.
- What is pityriasis rubra pilaris (PRP)?
- Cause of pityriasis rubra pilaris
- Cause is unknown
- Abnormal immune response
- Types or types of pityriasis rubra pilaris
- Type 1: Classic adult PRP
- Type 2: Atypical adult PRP
- Type 3: Classic juvenile type
- Type 4: Juvenile circumscript PRP
- Type 5: Atypical juvenile type
- Type 6: HIV-associated PRP
- Pityriasis rubra pilaris symptoms
- Skin
- Nails
- Complications
- Examination and diagnosis
- Physical examination
- Differential diagnosis
- Pityriasis rubra pilaris treatment
- Spontaneous recovery
- Ointments and creams
- Acitretin
- Methotrexate
- Ustekinumab
- Light therapy
- Prevention
- Timely initiation of treatment
- Prevent sunburn
- Prognosis and course of PRP
What is pityriasis rubra pilaris (PRP)?
Pityriasis rubra pilaris (PRP) was first described by Tarral in 1828 and the name was coined by Besnier in 1889. PRP is a rare, chronic skin disease of unknown etiology, characterized by orange-red scaly plaques, which are inflamed and sharply demarcated from normal skin. The skin around the hair follicles in particular is affected, resulting in numerous small red ‘islands’ appearing before the areas completely merge and turn red.
Cause of pityriasis rubra pilaris
Cause is unknown
The cause is unknown in 2023. A rare familial form of the disease exists, with an autosomal dominant form of inheritance where:
- one of the parents also has the condition;
- the condition occurs equally in men and women; and
- for each subsequent child of the same parents the chance of recurrence is 50%.
The hereditary form has been attributed to a mutation in the gene for CARD14.
Abnormal immune response
One hypothesis is that pityriasis rubra pilaris may be related to an abnormal immune response to an antigenic trigger. There are known cases of pityriasis rubra pilaris after a streptococcal infection, which is caused by species of the gram-positive coccus Streptococcus. PRP is not contagious.
Types or types of pityriasis rubra pilaris
Six types or types of pityriasis rubra pilaris are distinguished.
Type 1: Classic adult PRP
The most common variant of adult PRP is the classic form found in adults. The symptoms usually disappear after a few years. In some rare cases, symptoms return later.
Type 2: Atypical adult PRP
Atypical adult PRP also begins in adulthood. However, symptoms can last more than 20 years with this variant.
Type 3: Classic juvenile type
The classic juvenile form begins in childhood. The symptoms normally disappear within one year, but they may return later.
Type 4: Juvenile circumscript PRP
The juvenile circumscript PRP begins before puberty. It is most commonly seen on the palms of children’s hands, the soles of their feet, and their knees and elbows. The symptoms may disappear during the teenage years.
Type 5: Atypical juvenile type
In atypical juvenile PRP there is probably some hereditary factor. It may be present at birth or develop during early childhood. The symptoms often persist throughout life.
Type 6: HIV-associated PRP
HIV-associated PRP is linked to HIV infection. It is very difficult to treat.
Pityriasis rubra pilaris symptoms
Skin
PRP is characterized by red, flaky, inflamed skin that can cover quite large skin areas. The spots are quite sharply demarcated from the normal surrounding skin. Because the skin around the hair follicles is mainly affected, many small red ‘islands’ form between them before the areas merge and turn completely red. PRP can also occur around the genitals or body folds, armpits, groin and buttocks. PRP usually does not itch strongly.
Characteristic is keratinization of the skin (or the formation of calluses) on the palms of the hands and soles of the feet, which also turns red-orange.
Nails
The nails can also become involved in the process and turn yellow-brown, thicken (thickened toenails and fingernails) and show black spots. It is not uncommon for the nails to fall out at some point (onycholysis). In addition, other nail abnormalities are possible.
Complications
Pityriasis rubra pilaris can cause itching and discomfort. These symptoms may decrease over time, even if the rash appears to be getting worse. The condition usually does not cause many complications. However, RP can lead to problems with the mucous membrane of the mouth with irritation and pain. Over time, PRP can lead to keratoderma, where the skin on the palms of the hands and soles of the feet is thickened. Deep cracks and fissures can develop in the skin. Some people with PRP are also sensitive to light. They may have trouble sweating or difficulty regulating body temperature when they are hot.
Examination and diagnosis
Physical examination
The diagnosis is usually made on the basis of the clinical picture and a skin biopsy confirms the diagnosis. During a skin biopsy, the doctor removes a small piece of skin, which is then viewed under a microscope to make a diagnosis.
Differential diagnosis
PRP is often confused with other more common skin conditions, such as psoriasis. It can also be confused for less common skin conditions, such as lichen planus and pityriasis rosea. Psoriasis is characterized by itchy, flaky patches of skin that are often red. Unlike PRP, psoriasis can often be treated more easily and successfully. PRP should also be distinguished from the following skin conditions:
- atopic eczema
- dermatomyositis
- pompholyx (vesicular eczema, formerly called dyshidrotic eczema)
- an allergic reaction
- a cutaneous T-cell lymphoma (blood cancer)
- a fungal infection of the skin / athlete’s foot
- follicular eczema
- follicular ichthyosis
- keratosis pilaris
- systemic lupus erythematosus (SLE)
Pityriasis rubra pilaris treatment
Spontaneous recovery
PRP can remain active for months to years. In the vast majority of patients the condition resolves spontaneously within three years, but in a minority the condition persists for many years without signs of spontaneous recovery.
Ointments and creams
The use of oily ointments and creams is recommended to keep the skin in good condition and supple. Corticosteroids are only prescribed for limited areas. This is often combined with a horn dissolving agent and in some cases occlusion therapy is also prescribed, in which the areas are covered for a few hours with a special plastic bandage that contains a specific agent that loosens a thin layer of the epidermis.
Acitretin
For more extensive forms of PRP, the internal drug Acitretin (brand name Neotigason®) is prescribed. This is a substance derived from vitamin A.
Methotrexate
Methotrexate (MXT) is prescribed as a second choice for PRP. MTX is a drug that suppresses the immune system and inhibits inflammation. This medicine may disrupt liver functions.
Ustekinumab
If all other internal remedies do not provide relief, the doctor may recommend subcutaneous injections of ustekinumab. This biological suppresses the body’s defenses and inhibits inflammation. This can reduce the complaints.
Light therapy
Light therapy has not been shown to be effective in treating PRP and can even make PRP worse.
Prevention
Timely initiation of treatment
Because the cause of PRP is not known, you cannot prevent this condition. Consult your doctor as soon as you develop symptoms of PRP. Initiating adequate treatment in a timely manner is the key to relieving symptoms.
Prevent sunburn
Damage to the skin can cause PRP to worsen locally and sunburn aggravates the condition. Caution is therefore advised.
Prognosis and course of PRP
The progression depends on the type of PRP you have. The classic adult form probably lasts for a few years or less and then never returns. The classic juvenile form begins in childhood and is often in remission within a year. With atypical juvenile PRP, the symptoms are often present for life. Treatment can significantly alleviate the complaints.
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