A-Z OF SKIN

Acute dermatitis is a rapidly evolving red swollen itchy rash that tends to weep and form blisters. Whereas chronic dermatitis presents as an irritated thickened area of skin that can be red or darker in colour. The intermediate state is called subacute dermatitis.

Dermatitis skin can also split or fissure causing pain. Areas of crusting or tender blistering may suggest a bacterial or herpes virus infection complicating dermatitis.

The site affected depends on the specific type of dermatitis.

Some specific types of dermatitis

• Atopic dermatitis is caused by several factors including a significant inherited component. The skin has poor barrier function, making the individual more susceptible to developing dermatitis when exposed to environmental irritants/ allergens and during stressful periods. Infants commonly present with weeping crusted dermatitis on the face and neck. Older children and adults tend to have the creases of elbows/knees, wrists and ankles affected. The face or hands are often troublesome areas. There is an association between developing dermatitis and asthma or hay fever.

• Contact dermatitis is skin inflammation caused by an external substance that irritates the skin or causes an allergic reaction to occur. Irritant contact dermatitis is limited to the area of contact such as dermatitis under band aids, whereas allergic contact dermatitis starts at the area of contact and spreads beyond the contact area. The site affected by dermatitis depends on where an offending substance touches the skin.
• Seborrhoeic dermatitis is characterised by scaly red dry patches on the scalp, face and chest that are often not itchy. The condition can be worse during winter and during stressful periods. It is caused by an abnormal immune response to Malassezia yeast, a normal skin flora.
• Discoid eczema(nummular eczema) are coin-shaped itchy dermatitis patches on limbs and torso. Strong corticosteroids are often necessary to help settle the condition.
• Pompholyx(dyshidrotic eczema) is an extremely itchy blistering dermatitis on the hands and/or feet. It is usually triggered by heat, stress or inflammatory tinea.
• Venous eczema(stasis dermatitis) is characterised by an itchy red weeping rash on the lower leg(s) of older individuals with varicose veins. The affected areas often have brown haemosiderin (iron) stains and sometimes leg ulcer(s).
• Perioral dermatitis is a common irritable red rash around the mouth caused by the use of topical corticosteroid or heavy cosmetics and skin care products.

• Xerotic eczema (asteatotic eczema/eczema craquele) is characterised by red patches of dermatitis on a background of dry irritable skin, usually on the lower legs. The skin can look like cracked pavers.