A common skin disease that is caused by continuous itching: Lichen simplex chronicus

 

Itching is one of the most common symptoms in various skin diseases. The mechanism of itching is complex and still not well understood. But to put it in simple words, itching in a skin disease occurs as the disease itself produces chemicals that stimulate nerve fibres present in the skin which takes that neural information to brain via spinal cord and a specific region of brain gets stimulated which we perceive as itching sensation. To get relief from that sensation brain gives signals to our hands to do scratching or rubbing. But it is not the topic of today’s discussion.

Today I’m going to discuss about a disease where itching sensation followed by scratching and rubbing is the cause of the disease. Yes my friends. And that interesting disease is called Lichen Simplex Chronicus.

What is lichen simplex chronicus?

It is an itching associated with skin disease where continuous scratching or rubbing produces a single or sometimes multiple small lichenified (skin becomes thickened and leathery) elevated skin lesions. These skin lesions appear at some particular areas of skin which are easily accessible to our hands (so that scratching and rubbing can easily take place).

It occurs mostly in age between 30-50 years and women are more commonly affected than men.

 

How does it occur?

There is a dermatological and a psychological component to it. Patients who have other skin diseases like atopic dermatitis where itching is a main symptom, may develop lichen simplex chronicus due to continuous itching and scratching or rubbing. Patients who have the tendency of developing lichen simplex chronicus may develop the disease due to psychogenic itching. Anxiety and depression play a major role in these patients.

The continuous itch-scratch cycle produces the changes in the skin. The skin becomes rough, thick and leathery due to continuous friction.

 

Where does it occur?

It mainly occurs over the easily accessible areas like back and sides of the neck (patients with long history of polymorphous light eruption^{https://drsupratim.blogspot.com/2022/03/most-common-photo-induced-skin-rash.html} over the back of the neck may develop lichen simplex chronicus at that site), lower legs, ankle, forearm, upper thigh, scrotum and valva.

How does it look (clinical features)?

Initially the area of the skin is reddened and slightly thickened. With time the redness disappears and that area becomes more thick and leathery, hyperpigmented and slightly scaly. As the name suggests it looks like lichen (a plant that grows over rocks, walls and trees and looks crusty) over a tree bark.

Initial lesion of lichen simplex chronicus

A very typical and diagnostic feature is over prominence of normal skin markings over the affected area.

       

Well formed lesions of lichen simplex chronicus

 

Are there any investigations needed?

The diagnosis is done clinically and usually no investigation is needed.

 

Do you need to go to a dermatologist?

Of course yes. For most obvious reason is that it needs proper treatment. And secondly because it needs to be differentiated from other similar looking diseases like lichen planus, lichen planus hypertrophicus, lichen amyloidosis and psoriasis.

                                           

Lichen planus hypertrophicus                                                Lichen amyloidosis

 

What is the Solution?

I am not mentioning any kind of medications or name of any medicines or creams to avoid self-medication.

You must visit a dermatologist for proper treatment of this condition.

But I am just mentioning the treatment components here.

·       Discussion about the disease process and prognosis with proper counselling is very important part of treatment.

·       Breaking the itch-scratch cycle is very important. So itching needs to be reduced by proper medications.

·       Along with that the affected area has to be treated locally by applying proper cream.

·       The underlying disease (like atopic dermatitis or polymorphous light eruption) has to be treated.

·       If there is any psychological component present then help of a psychiatrist may be needed.

 Source

1. https://www.medindia.net/news/healthinfocus/scratch-that-itch-brain-mechanism-identified-184546-1.htm?msclkid=f416fa29aeba11ec9edb90a7e605644c
2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4081479/?msclkid=de84324baeb911eca0e1da49057395a1
3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3170689/?msclkid=20fd50dbaeb811ec8f0f58de0fccda3e
4. Rook’s textbook of dermatology, 9^th edition, chapter 83
5. https://medlineplus.gov/ency/article/003251.htm?msclkid=ce70c9ddaec911ecbf14005045c70828