Types of hand eczema. Is it different from underarm rash

Most people suffer from mild degrees of hand eczema, as dryness or chapping, sometime or other during their life time. Hand dermatitis and underarm rash are more common in females to the ratio of 2:1. In most of the cases the condition is self limiting, but if spreads further a visit to eczema specialist is a must.

hand eczema

Pompholyx

Pompholyx is also known as dyshidrotic eczema or vesicular eczema of the palms and soles, as most of the time the soles are also affected. Tense fluid filled, intensely itchy vesicles appear on the sides of fingers and palm. Hereditary predisposition, emotional stress, ide eruption to fungal or bacterial infections, ingested allergens, chromate and nickel sensitivity all have been cited as causes for pompholyx. This is a bit different from underarm rash.

Recurrent Focal Palmar Peeling

Previously known as keratolysis exfolitiva, this is probably a minor form of pompholyx. Mostly in summer, small areas of scaling appear on the palms and soles and peel off abruptly. These are self limiting and require no treatment. It is common in underarm rash and is self limiting.

Hyperkeratotic Palmar Eczema

Thought to be the result of chronic irritant contact dermatitis, this type of thick, keratotic scaly hand eczema, also known as tylotic eczema, is very difficult to differentiate from psoriasis of the palms. The dermatitis is highly irritable and painful, and is responsible for 2-5% of all applications for permanent disability in some western European countries. Treatment resistant, better response is seen to PUVA phototherapy and oral retinoids than to topical super potent steroids.

Ring Eczema of the Hands

Commonly seen in young women wearing broad rings, this type of hand eczema is caused by detergents, soaps and cosmetics under the ring. A radiation eczema caused by radioactive gold in rings can also cause similar dermatitis. It is suggested to use specially made hand soap for eczema.

Dry Palmar Eczema (Wear and Tear Hand Dermatitis)

Also known as dry hand eczema or housewives’ dermatitis, dry hand eczema is caused by frequent exposure to water and detergents. This can also be treated with specially made hand soap for eczema.

Fingertip Eczema

Typically involving the finger tips (palmar side) of the dominant hand, this is due to chronic exposure to occupational irritants or allergens.

Apron Eczema

This type of hand eczema involves palmar aspect of two or more fingers near to the palms and the sides of palms. This is usually caused by holding or wringing clothes immersed in detergents. Specially made hand soap for eczema can easily treat such apron eczema. If not, pay a visit to a eczema specialist.

Discoid Eczema

Discoid eczema of the hands affects the back of the hands and the back or sides of individual fingers. Forearms may also be involved. The scaly plaques can occur on a previous site of burns, a local chemical or irritant reaction. It is similar to underarm rash and need to visit a eczema specialist.

‘Gut’ Eczema

Also called slaughterhouse eczema, this is caused by contact with slaughterhouse animal blood, flesh and fat. Involves the finger webs and sides of fingers. Organic eczema cream can give relief initially but if it is not cured, a visit to organic eczema cream is a must.

Other Types: Patchy Vesiculo-squamous Hand Eczema

A patchy hand eczema with blisters and scaling appear randomly. This hand eczema is believed to occur due to irritant contact dermatitis and is similar to underarm rash.

The morphological and distribution pattern of these different types of hand eczema may vary. Finding the exact cause of the hand eczema is indeed important in taking preventive and curative steps to get rid of the hand eczema.

How Does Itching Occur?

Itching, or pruritus, can be defined as an unpleasant sensation which elicits a desire to scratch. The causes of itching are many; in fact, any irritation of the skin and its structures can cause the ubiquitous itchy sensation in most individuals.

Itching varies in intensity and has been described as mild, ticklish, burning, prickly, pricking, crawling sensation under the skin, persistent, intermittent or severe in different diseases. Itching may be generalized or localized, and with or without skin rashes. Itchy scalp, itchy palms and soles, itchy genitals (itchy vulva and itchy scrotum), and itchy anus are the special localized types of itching.

In lower mammals, itching is of positive biological value in getting rid of insect infestations. In humans, though, the itch causes skin abrasions, and often signs of skin inflammation in the form of dermatitis.

Clinically, the itchy skin may be classified as itching without skin rash and itchy skin with identifiable skin eruptions. In a 2003 article titled “Itch: Scratching more than the surface” in the Quarterly Journal of Medicine (Volume 96), Twycross et al., classified itching according to the following basic pathological causes:

Pruritus due to irritation of itch receptors in the skin: Skin diseases like scabies, drug reactions, urticaria, dermatitis herpetiformis, insect bite reactions, eczema, and contact dermatitis cause itching through this mechanism.

Itching due to neuropathic diseases affecting the peripheral and central nervous system, as in peripheral neuropathy or brain tumors.

Neurogenic itchy skin due to chemical mediators affecting the central nervous system without causing structural damage to the nervous system, as in opioid peptides produced in cholestatic liver diseases.

How Does Scratching Relieve the Itch?

Itch impulse is induced in the skin through the release of chemical mediators, especially histamine, which stimulate special “raw” nerve endings within the skin. The itch sensation is then transmitted from the skin through specialized sensory fibers to the brain, through the thalamus, where it is perceived as an urge to scratch. This stimulates a reflex scratch impulse through the spinal axons which is also modified through the higher brain centers.

Scratching activates suppressor neurons in the cerebral cortex (in an area known as substantia gelatinosa, which is also the “gate” control of pain) resulting in the reduction of the itch sensation. An April 2009 University of Minnesota study by Davidson et. al. found that scratching resulted in stoppage of further itch signals at the spinal level of neurons rather than at the cerebral cortex.

Any mechanical (stroking, vibration), thermal (mild heat), chemical (irritants like acids and alkalies), many pharmacological agents (especially histamine, morphine, codeine, serotonin, cytokines, proteases and opioid peptides can initiate the itch sensation in the skin. In addition, any skin diseases which irritate the skin, like dry skin or inflammatory skin diseases can also be the cause of the pruritus.

In certain skin diseases like neurodermatitis and prurigo nodularis, the itch-scratch cycle produces pathological changes even in the nerve endings, causing them to enlarge and cause intense itchy sensation even on mild stimulation locally or through the psycho-neurological pathway. In such diseases, the itching and scratching could produce an incessant and vicious itch scratch cycle making life a misery for the sufferer.

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