Dermatitis

Contact Dermatitis

Contact dermatitis is an acute or chronic skin inflammation that occurs when the skin comes in contact with a substance that causes a type IV delayed hypersensitivity reaction(allergic contact dermatitis) or when there is an injury to the skin’s surface (irritant contact dermatitis), or when the allergen or irritant is activated by sunlight hence Phototoxic dermatitis occurs.

Types of Contact Dermatitis

1. Allergic dermatitis. Allergic dermatitis results from direct contact with substances called allergens, such as nickel, chlorine, presenting with; Skin reddening, Blisters that ooze, Itching which can become intense., Swelling in eyes, face and genital areas in severe cases.
2. Irritant contact dermatitis. This is the most common form of contact dermatitis, Irritant contact dermatitis develops when your skin comes into contact with an irritating substance. Irritant contact dermatitis is either acute or chronic, according to the strength of the irritant, such as acids, kerosene. Stiff, tight feeling skin. May present with mild swelling, Dry, cracking skin, Blisters, Painful ulcers.
3. Phototoxic contact dermatitis.  It is further divided into two categories, phototoxic and photoallergic contact dermatitis. Phototoxic contact dermatitis is a sunburn-like skin disorder resulting from direct tissue damage following the ultraviolet light-induced activation of a phototoxic agent. It is usually associated only with areas of skin which are left uncovered by clothing especially during scans and x-rays.

Causes of Contact Dermatitis

Contact dermatitis is caused by exposure to a substance that irritates your skin or triggers an allergic reaction, such irritants include;

• Soaps. Most kinds of soaps, detergents, shampoos and other cleaning agents have harmful substances that could possibly irritate the skin.
• Solvents. Solvents such as turpentine, kerosene, fuel, and thinners are strong substances that are harmful to the sensitive skin.
• Extremes of temperature. There are people who are highly sensitive even when exposed to extremes of temperature and could cause contact dermatitis. 
• Products that cause a reaction when you’re in the sun (photoallergic contact dermatitis), such as some sunscreens and cosmetics
• Formaldehyde, which is in preservatives, cosmetics and other products
• Personal care products, such as body washes, deodorants, hair dyes and cosmetics
• Plants such as poison ivy and poison oak, cashew nuts, which contain a highly allergenic substance called urushiol
• Airborne allergens, such as pollen and spray insecticides
• Nickel, which is used in jewelry, and many other items
• Medications, such as antibiotic creams, and there side effects such as diazepam, ceftriaxone.
• Latex and long exposure to wet surfaces such as staying in a wet diaper for a long time.

Signs and Symptoms

Allergic dermatitis is usually affects the area where the trigger has touched the skin, while irritant dermatitis may be more widespread on the skin. Clinical features of both forms include the following:

• Red rash. This is the commonest reaction. The rash appears immediately in irritant contact dermatitis and later in allergic.
• Blisters or hives. Blisters and hives     may present in a pattern where skin was directly exposed to the allergen or irritant.
• Burning skin. Irritant contact dermatitis tends to be more painful than itchy, causing swelling, burning or tenderness
• Itching. Once the patient is exposed to an irritating substance, the patient presents with severe itching.
• Crusting. The vesicles start to form a crust as it slowly becomes dry, cracked, and scaly skin.
• Hyperpigmentation. Leathery patches that are darker than usual often because of scratching from irritation.

Diagnosis of Contact Dermatitis

• Diagnosis is done by performing patch test. In this test, small samples of a chemical are placed on an area of skin to see if a rash develops.
• Thorough history taking where the child mentions of use of certain products that are in contact with his or her skin.
• Note; There are no tests for irritant contact dermatitis, only history of irritating substance that a child regularly come into contact with will prove that a child has irritant contact dermatitis.

Treatment of Contact dermatitis

• The form of treatment will depend on the cause of dermatitis. Common treatments include;

1. Cortisone-type creams. In severe cases, drugs containing cortisone may be given orally.
2. Antihistamines. These are itching relievers.
3. Dry skin care by use of lotions and creams.
4. Oatmeal baths also to relieve itching.
5. Barrier cream. These products can provide a protective layer for the skin.
6. Avoiding the irritant. The key is to identify the substance that causes the rash so that it could be avoided.

Prevention

      For allergic contact dermatitis,

• Avoid contact with substances that cause the skin rash.
• Wash any child’s area that comes into contact with allergic substances.
• Learn to recognize and remove poison oak and poison Ivy plants from playing areas of children

   For irritant contact dermatitis,

• You can also use petroleum jelly to protect the child’s skin. Reapply the petroleum jelly two to three times a day and after washing hands.
• Avoid contact with substances that irritate the child’s skin.
• Use mild soaps.
• Use hand creams frequently.

Question.

 Contact dermatitis is a type of hypersensitivity: 

A. Type I.
B. Type II.
C. Type III.
D. Type IV.

4. Answer: D. Type IV.

• D: Type IV hypersensitivity is a delayed hypersensitivity reaction that are inflammatory in nature initiated by mononuclear leukocytes.
• A: Type I hypersensitivity is triggered by an innocuous foreign substance (like dust, pollen or animal dander) that would cause no problems in the majority of people.
• B: Type II hypersensitivity is the process by which IgG or IgM binds to a cell to cause injury or death (Antibody Dependent Cytotoxicity).
• C: Type III hypersensitivity is tissue damage created by immune complexes, which are aggregations of antigen and antibodies.