Skin condition like psoriasis

Flexural psoriasis

Psoriasis is a common scaly skin condition resulting in red scaly and thickened patches of skin. Flexural psoriasis is sometimes called inverse psoriasis and describes psoriasis localised to the skin folds and genitals. Common sites of flexural psoriasis are:

  • Armpits
  • Groin
  • Under the breasts
  • Umbilicus (navel)
  • Penis
  • Vulva
  • Natal cleft (between the buttocks)
  • Around the anus

Many patients have psoriasis affecting other sites, particularly inside the ear canal, behind the ears, through the scalp, and on elbows and knees.

  • See more images of flexural psoriasis …
  • See more images of genital psoriasis …

Clinical features of flexural psoriasis

Due to the moist nature of the skin folds the appearance of the psoriasis is slightly different. It tends not to have silvery scale, but is shiny and smooth. There may be a crack (fissure) in the depth of the skin crease. The deep red colour and well-defined borders characteristic of psoriasis may still be obvious.

Scaly plaques may sometimes occur however, particularly on the circumcised penis.

Flexural psoriasis can be difficult to tell apart from seborrhoeic dermatitis, or may co-exist. Seborrhoeic dermatitis in skin folds tends to present as thin salmon-pink patches that are less well defined than psoriasis. If there is any doubt which is responsible, or there is thought to be overlap of the two conditions, the term sebopsoriasis may be used.

Complications of flexural psoriasis include:

  • Chaffing and irritation from heat and sweat
  • Secondary fungal infections particularly Candida albicans (thrush)
  • Lichenification (a type of eczema) from rubbing and scratching – this is a particular problem around the anus where faecal material irritates causing increased itching
  • Sexual difficulties because of embarrassment and discomfort
  • Thinned skin due to long term overuse of strong topical steroid creams

What is the treatment for flexural psoriasis?

Flexural psoriasis responds quite well to topical treatment but often recurs.

Topical steroids
Weak topical steroids (often in combination with an antifungal agent to combat thrush) may clear flexural psoriasis but it will usually recur sometime after discontinuing treatment. Stronger topical steroids need to be used with care and only for a few days, thinly and very accurately applied to the psoriasis. If the psoriasis has cleared, stop the steroid cream. The steroid cream may be used again short-term when the condition recurs.

Overuse of topical steroids in the thin-skinned body folds may cause stretch marks, marked thinning of the skin and can result in long term aggravation of psoriasis (tachyphylaxis).

Vitamin D-like compounds
Calcipotriol cream is an effective and safe treatment for psoriasis in the flexures and should be applied twice daily. If it irritates, it can be applied once daily and hydrocortisone cream 12 hours later.

Topical calcineurin inhibitors
Topical calcineurin inhibitors Tacrolimus ointment and pimecrolimus cream may be effective and do not cause skin thinning.

Combinations of the treatments listed above may be used, together with emollients. Antiseptics and topical antifungal agents are often recommended as flexural psoriasis may be complicated by bacteria and yeasts, including Candida albicans and Malassezia.

Strong topical agents
Treatments that are tolerated in other sites are often too irritating to use in skin folds, e.g., dithranol, salicylic acid and coal tar. However, it may be possible to use them by diluting in emollients, or by applying them for short periods and washing off.

Systemic agents are rarely required for limited flexural psoriasis and phototherapy is relatively ineffective because the folds are hidden from light exposure.

Psoriasis causes

Psoriasis is caused by excessive inflammation in the skin. This causes rapid growth and shedding of skin cells, which build up into thick, red and scaly patches.

Psoriasis is a genetic condition, which means it runs in families.

It isn’t contagious.

Psoriasis symptoms

The symptoms of psoriasis are red patches of skin that have silvery-white scales. These patches aren’t usually itchy.

Psoriasis can come up anywhere on the body, but it most often comes up on the scalp, knees, elbows, belly button and between the buttocks. Psoriasis also affects fingernails and toenails. If you get it on your nails, they might look pitted, discoloured or thickened.

You can get psoriasis at any age, although children get it less often than adults. In young children it might come up in the nappy area, and you might think it’s nappy rash.

Your child might get a spotty type of psoriasis (called guttate psoriasis) after a mild respiratory infection – for example, tonsillitis. This type of psoriasis usually lasts for a few months before fading.

Some people can develop psoriatic arthritis, but this is uncommon in children.

When to see your doctor about psoriasis symptoms

If your child has a rash, see your GP. The GP can advise you on the right treatment.

The GP might refer your child to a paediatric dermatologist for further assessment.

Psoriasis treatment

There’s no cure for psoriasis, but there are many treatments that can make the rash go away and reduce symptoms.

The right treatment for your child will depend on her age, the area of her body that’s affected, and how bad her symptoms are.

Treatment involves ointments and creams, including corticosteroids (cortisone), tar preparations and vitamin D creams (calcipotriol). If your child has widespread psoriasis, a course of ultraviolet B light might help.

In very severe cases your doctor might prescribe an immunosuppressant or biological drug.

If the psoriasis has appeared after a recent bout of tonsillitis, your doctor might also consider prescribing antibiotics.

It’s essential to moisturise your child’s skin. Use simple moisturisers like Vaseline, Dermeze, aqueous cream and sorbolene cream. This will help the skin growth and shedding rate come back to normal levels.

Is It Psoriasis, Eczema, or Something Else?

Psoriasis is the most common autoimmune disease in the United States. According to the National Psoriasis Foundation, about 7.5 million Americans are affected. Yet despite its prevalence, many people still don’t know what it is — or what it looks like.

Psoriasis is a chronic autoimmune condition that speeds up the growth of skin cells and causes dry, itchy, and sometimes painful lesions or bumps on your body. It may sometimes be mistaken for eczema or dermatitis.

To distinguish psoriasis from these and other skin conditions, it is helpful to know how psoriasis itself can appear. Each type of psoriasis has different features:

  • Psoriasis vulgaris (plaque psoriasis). This is the most common form of the disease, accounting for about 80 to 90 percent of cases. It causes symmetrical, well-defined, itchy, bright red, raised patches, or plaques, which are covered by silvery scales. The plaques can appear on most any part of the body other than mucous membranes, but typically will show up on elbows, knees, shins, the lower back, the belly button, and the buttocks’ crease.
  • Guttate psoriasis. This form of the psoriasis appears suddenly as small red spots that look like drops. It is often linked to a streptococcal or other bacterial infection.
  • Inverse psoriasis. This is a type of psoriasis that typically appears in the armpits, groin, under the breasts, and in skin folds around the genitals and buttocks. Inverse psoriasis is so named because it’s most common in areas usually spared by the more common plaque-like psoriasis. However, it is possible to have both forms at the same time. The affected patches are usually very red but lack scales.
  • Pustular psoriasis. This form of psoriasis is distinguished by pus-filled bumps on the skin. It can be triggered by certain medications, topical agents, UV light, infections, pregnancy, and stress.
  • Erythrodermic psoriasis. This variation of psoriasis causes a bright red sheen to form on large sections of the body that looks similar to the shell of a cooked lobster. The affected areas are usually very itchy and painful.

Skin Conditions That Look Like Psoriasis

Other skin conditions might seem like psoriasis, but there are differences, from the shape of the borders of the affected areas to the color and thickness of the scales. Here are some similar-looking skin conditions that may even occur simultaneously with psoriasis:

  • Seborrheic dermatitis (seborrhea). While this can be confused with plaque-type psoriasis, the scales of psoriasis tend to be thicker and the lesions have much more clearly defined borders. Seborrhea involves only the oil-producing areas of the skin around the scalp, face, chest, and, less frequently, groin and upper back. Seborrhea lesions are poorly defined and pink with yellow-brown scales. A rash on the face could be either psoriasis or seborrheic dermatitis, and the two conditions can appear at the same time.
  • Dandruff. Seborrhea on the scalp, known as dandruff, produces fine, greasy scales and usually is distributed generally over the head.
  • Eczema. Atopic dermatitis, or eczema, is more common than psoriasis and more likely to be diagnosed by primary care physicians. It appears frequently on the back of the knee or in front of the elbow — a much more limited area than the common forms of psoriasis. What triggers the rash also helps differentiate atopic dermatitis from psoriasis. Atopic dermatitis can be brought on by outside irritants such as dust, foods, or pollen. In addition, the skin lesions of eczema can get infected with bacteria. By comparison, such irritants generally do not trigger psoriasis, and psoriasis lesions are not usually susceptible to secondary infections.

Other more serious conditions that mimic the appearance of psoriasis include mycosis fungoides, a rare form of lymphoma, and pityriasis rubra pilaris, a rare skin disorder.

Getting the Right Diagnosis

Your doctor might do a biopsy in the case of an unclear diagnosis or when the psoriasis is particularly severe. A biopsy allows the dermatologist to look at a tissue sample under a microscope. Examination of the cell architecture, blood vessels, and other structures can help distinguish psoriasis from lookalike conditions.

“Several diseases have overlapping characteristics — often it’s not black and white,” says Stephen Templeton, MD, a dermapathologist and dermatologist with Finan-Templeton Dermapathology Associates in Sandy Springs, Georgia.

When a person has more than one skin condition, a complete and precise diagnosis will allow a physician to avoid treatments that interfere with each other or interact negatively. Because some psoriasis treatments can have significant consequences, such as possible liver damage associated with the drug methotrexate, an accurate diagnosis is especially crucial, says Dr. Templeton.

Psoriasis is a disease that causes people to develop thick patches of inflamed skin covered with silvery scales. It’s an autoimmune disease, meaning that the immune system becomes overactive and attacks healthy cells in the body by mistake.

With psoriasis, an overactive immune system leads to skin cells that grow too quickly: New skin cells form in days rather than weeks, which causes them to build up rapidly on the surface of the skin, forming the characteristic thick patches and scales of psoriasis, according to the National Psoriasis Foundation.

In people with light-colored skin, psoriasis looks like salmon-pink plaque with an overlying whitish scale, said Dr. David Rosmarin, a dermatologist at Tufts Medical Center in Boston. The most common locations affected are the elbows, knees, scalp, lower back and backside, and the genitals may also be affected, he said.

On people with dark-colored skin, those skin patches look more violet or purplish, with a gray scale, according to the American Academy of Dermatology.

About 7.5 million people in the U.S. have psoriasis. The most common type is plaque psoriasis, which affects about 80% of people, according to the American Academy of Dermatology.

Plaque psoriasis is one of the five types of psoriasis that affects adults and children. (The other four types are guttate, pustular, inverse and erythrodermic.) It’s possible to have more than one type of psoriasis at the same time, Rosmarin said.

What does psoriasis look like?

Itchiness is the most common complaint in people with psoriasis, Rosmarin told Live Science. People feel itchy especially when psoriasis affects their scalp, palms of the hands or soles of their feet, he said.

According to the Mayo Clinic, the most common physical symptoms of plaque psoriasis include:

  • Skin with raised, pink to reddish patches called plaque.
  • Patches may be covered with a silvery-white coating called scale.
  • Skin that may feel itchy, or may burn, sting or be painful.
  • Patches that may crack and bleed.
  • Fingernails and toenails may look pitted, cracked, thickened or crumbly, and might be confused with nail fungus.

The skin disease may also take a psychological toll, as evidenced by higher rates of depression, anxiety and substance abuse found in people with psoriasis, Rosmarin said.

Psoriasis can show up anywhere on the skin, and the patches can appear separately or join together to cover a larger area. When patches and scales are in visible locations, people with psoriasis may feel self-conscious or withdraw socially.

“Some of my patients with psoriasis won’t go out with shorts or short-sleeved shirts in the summer,” Rosmarin said. Similarly, some of Rosmarin’s patients with scalp psoriasis refuse to wear black shirts because they’re worried about the visible dandruff from their shedding scales, he said.

Here’s a simple drawing of what normal, healthy skin looks like compared to skin with psoriasis. (Image credit: )

Causes, risk factors and triggers

It’s unclear what causes psoriasis, but an immune system that is too active as well as genetic and environmental factors may be responsible, Rosmarin said. People with a family history of psoriasis and those who have had viral or bacterial infections, such as strep or skin infections, are more likely to develop psoriasis, he said. But psoriasis is not contagious, so a person can’t get it by touching the skin patches of someone who has it.

Another theory is that psoriasis may be spurred by a traumatic injury to the skin, such as burns, animal bites or tattoos, Rosmarin said.

The following factors may trigger flare-ups of psoriasis, making the condition worse for a few weeks or months, according to the National Psoriasis Foundation.

  • Infections, such as strep throat or skin infection. Psoriasis may flare up in children two to six weeks after an earache, tonsillitis, bronchitis or respiratory infection.
  • Skin injury, such as a cut, scrape or bad sunburn.
  • Stress can cause psoriasis to flare up for the first time or aggravate the skin disorder in those who already have it.
  • Use of certain medications, such as beta blockers, lithium and antimalarial drugs.

Diagnosis and treatment

A dermatologist will examine a person’s skin, nails and scalp for signs of psoriasis, as well as ask whether any family members have the disease. If psoriasis is suspected, a small sample of affected skin (biopsy) may be removed and viewed under a microscope: Skin with psoriasis looks thicker and inflamed compared with skin with eczema, for example.

Psoriasis can develop at any age. People are typically diagnosed in their 20s, but there is a smaller peak period later in life between ages 50 and 60, Rosmarin said.

With the current advancement in treatment methods, dermatologists can help the vast majority of patients with psoriasis much more than they could have just a decade ago, Rosmarin told Live Science.

There are four categories of treatment available to people with psoriasis: Topical creams and ointments; phototherapy (exposure to ultraviolet light); oral medications; and biologics, which are drugs given by injection (shots) or intravenously, Rosmarin said. The treatment a person with psoriasis receives depends on the severity of their case and their overall health.

Arthritis and other health effects

Although psoriasis is a skin disease, it can influence a person’s health in a number of different ways. For example, some people with psoriasis have an increased risk of developing psoriatic arthritis, an inflammatory form of arthritis. About one-third of people with psoriasis get this type of arthritis, which causes joint pain and stiffness, Rosmarin said. Without treatment, psoriatic arthritis can cause structural damage to the affected joints, he said.

People with moderate to severe forms of psoriasis are also at a higher risk of cardiovascular disease, such as heart attack and stroke, Rosmarin said. This might be because psoriasis triggers long-lasting inflammation in the body that can affect the skin and joints and may also affect the heart and blood vessels, he said.

Additional resources:

  • Learn about the different types of psoriasis and what they look like from the American Academy of Dermatology.
  • See how psoriasis looks different in light- and dark-skinned people, according to the American Academy of Dermatology.
  • Find out more about psoriatic arthritis from the National Psoriasis Foundation.

This article is for informational purposes only, and is not meant to offer medical advice.

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