Most common photo-induced skin rash - PMLE: Ultimate guide to patients

 

It was the weekend and you just went to the nearby beach to have some fun. The next morning you suddenly realized that you are having some itchy skin rash over your back of the neck and upper arms. It could be PMLE.

Or

Your summer holiday has just started and after few days of outdoor activity there is itching and rash over the chest and upper back. It might be PMLE.

So what is PMLE?

PMLE stands for Polymorphous Light Eruption

P-Polymorphic/polymorphous – several different forms or characters

L- light induced

E- Eruption – spot or rash over skin

PMLE is the most common type of photo induced skin rash that generally occurs over sun exposed areas of skin after a certain period of intense exposure to sunlight (Ultra violet ray).

Who gets this type of skin rash?

It is the most common photo induced skin problem.

Most commonly occurs in age between 21-30 years and more common in females ⁽¹⁾.

According to various Indian studies it affects around 2-13.5% people in various parts of India ⁽²⁾.

How does it feel (clinical features)?

It particularly occurs after a delay of at least 6 hours to few days following the exposure to high intensity sunlight. Exposure can be for 10 minutes to several hours.

If no further exposure to Ultra Violet Ray(UVR) occurs, then it usually resolves within 7-10 days without scarring.

As the season progresses your skin may become less sensitive and symptoms may occur in less severe manner.

Skin lesions are polymorphous which means it can be of various characters, size and shape but in a single patient usually one type is seen. In my practice I have seen patients most commonly present with groups of whitish or skin coloured or reddish tiny bumps over sun exposed areas. Larger elevated lesions (plaques) or fluid filled bumps(vesicles) are seen less frequently.

Back of the neck, upper back, chest, outer side of upper arm and forearm are commonly affected sites. Face and hands are less commonly involved as they become tolerant due to exposure to sunlight from childhood.

Why does this skin rash occur?

Exact reason is unknown.

But from various studies and investigations few things are suggested.

I will try to be as simple as possible.

When UVR falls on skin there is some changes that occur on the skin. This change can trigger our immune system and an immune reaction occurs which causes the disease.

Normally when UVR falls on skin it induces an immune suppression which inhibits immune reaction. But in PMLE patients this UVR induced immune suppression is inhibited.

There is some role of genetic and hormonal factors.

But there is some good news

Due to inhibited UVR induced immune suppression patients with PMLE are less susceptible to develop skin cancer. In simple words if you have PMLE then you have less chance of getting skin cancer.

Are there any investigations needed?

Diagnosis is mainly done by taking thorough history and clinical examination.

If there is any confusion or if it needs to be differentiated from diseases like lupus erythematosus then some investigations and biopsy may be required.

Disease course and prognosis

It's a chronic disease which appears intermittently for years. In some cases, the severity decreases with time and may get cured after years. But the prognosis is usually good as many cases are self limiting and in severe symptomatic cases response to treatment is generally very good. In my practice I have seen that most patients get cured only by applying a single cream for few days with adequate photo protection.

Do you need to consult a dermatologist if you have similar skin rash?

Yes of course.

Treatment

Patient counselling and informing the patient with disease course and prognosis is very important because in most of the cases this disease causes enough psychological stress as it mainly occurs over the visible parts of the body.

When a patient presents with PMLE with severe itching firstly symptomatic management to alleviate the symptoms is needed which is done by proper medications which I should not discus here.

Second step is prevention which is done by photo protection. Physical photo protection by using umbrella, hat, protective clothing (like full sleeve shirts for men) are important. Protect your back of the neck with a scarf. For women blouse which covers the whole upper back and chest is very helpful. Along with that proper sunscreen can also be suggested.

Source

1. https://www.ijord.com/index.php/ijord/article/view/92?msclkid=421a9260a6b711ec95844fa6d7c90f4d
2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8088173/?msclkid=4219d97ca6b711ecb4af8fed5226bda4
3. Rook’s textbook of Dermatology, 9^th edition, chapter 127
4. Fitzpatrick’s Dermatology, 9^th edition, chapter 92

 

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Alopecia areata (a hair losing disease): The ultimate guide for patients

 One fine evening you just took a shower and you were getting ready for a party…while styling your hair you suddenly felt something odd…you just asked your mom to look and oh my goodness me…what is this…a round patch of baldness suddenly came from nowhere. That just might be alopecia areata.

Or

You are having hair fall issues for few weeks. Suddenly people start asking you why your hair is becoming greyer day by day. Are you suddenly becoming old? Certainly not. That might be alopecia areata as well.

Or

You just have had a clean shave few days back for a date. After few days when the beard starts to grow, you suddenly realize there is a round area where the beard is not coming back. And you might be thinking who ate that. Sorry, no one. It’s also a type of alopecia areata.

Though it’s not as common as pimples but alopecia areata has a global prevalence of around 2% ^{(https://pubmed.ncbi.nlm.nih.gov/31437543)}

I used to work in a govt. hospital OPD, where around 200-300 patients used to come daily. Among them I found at least 2-3 patients with alopecia areata daily. Most of them are aged between 10-40.

What is alopecia areata?

It is a hair losing disease, causing rapid and complete loss of hair from one or more round or oval patches, most commonly from scalp, bearded areas, eyebrows and less commonly from other hairy parts of the body.

How can you diagnose alopecia areata as a patient?

1.    Sudden appearance of a round or oval patchy hair loss of 1-5 cm in diameter over scalp or bearded area or eyebrows or any other hairy part of body.

2.    There may be single or multiple patches. Patches may join to form large area of hair loss. Complete loss of scalp hair can occur (alopecia totalis). Complete loss of all body hair may also occur (alopecia uliversalis).

3.    Spontaneous regrowth can occur over a patch. Newly growing hairs are typically grey or white which can regain pigmentation later on.

4.    White hairs are rarely affected. So if you have white and black hair evenly distributed over your scalp then you may notice that hairs are becoming greyer or whiter within days. It can occur in case of diffuse alopecia areata which is difficult to diagnose.

5.    There may be some changes in your nail in severe cases like pitted nail (small depressions on nail surface), rough nail etc.

Why does alopecia areata occur?

See, our immune system is built to protect us from foreign particles like bacteria or virus. But when our own immune system works against our own body then it causes autoimmune disease (over simplified). Alopecia areata is a type of autoimmune disease. Here T-Lymphocytes (a cell of our body which is a part of our immune system) gets activated and attacks hair producing cells. That causes hair loss. But it does not destroy the hair follicle fully. And that is why hair loss in this disease can be reversible.

Genetic factors also have some role. About 25% patients have positive family history.

What are the other important things to keep in mind?

1.    Other autoimmune diseases like thyroiditis, lupus erythematosus, psoriasis or vitiligo may be associated with it.

2.    Patients with atopic dermatitis (a type of eczema in short) may present more severe disease and at an earlier age.

3.    So if you have other health issues or problems, you must share everything in details with your doctor.

Why should you visit a qualified dermatologist ASAP?

See, my intention to create this post is to enlighten and to educate the patient, not to diagnose the disease and start self-medication. This is not a kind of disease where you can treat yourself at home without consulting a doctor.

In children, a similar looking alternate possibility is tinea capitis (a fungal infection of scalp). Androgenetic alopecia, early lupus erythematosus, syphilis are some other possibilities. You can’t differentiate between these diseases by your own. Neither you can treat any of these diseases by yourself.

As there may be spontaneous regrowth of hair in some cases, you might be reluctant to go to a doctor. You may think that the problem will get cured by its own. But during that phase of regrowth suddenly a new patch of hair loss may appear within days.

If the re-growing hair remains grey or white for long duration, there is a possibility of associated vitiligo. So you must visit a qualified dermatologist as soon as you detect the problem.

Prognosis

In my practice I have seen more than 50% patients had complete recovery within 6-12 months. Even in a patient with alopecia totalis, compete hair regrowth was achieved by proper treatment within 8 months. But unfortunately most of the patients come with similar episodes in the future.

Association with atopic dermatitis, early age on disease onset and more extensive involvements are some bad prognostic factors.

What can you do?

1.    Try to recognize the problem as soon as possible.

2.    Maintain proper diet rich in vitamins, minerals and antioxidants.

3.    Avoid foods with high sugar content.

4.    Seek help of a specialist ASAP.

What should you not do?

1.    Don’t panic and don’t get over stressed.

2.    Don’t delay in seeking help from a qualified dermatologist.

3.    Do not self-medicate yourself or apply anything on your scalp without consulting your dermatologist.

Treatment

Multiple treatment modalities are available. Let your dermatologist chose the best treatment for you.

Source

1.    https://pubmed.ncbi.nlm.nih.gov/31437543/

2.    Andrew’s diseases of the skin – clinical dermatology, 12^th edition, chapter 33

3. Rook’s textbook of dermatology, 9^th edition, chapter 89

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