Pathogenesis and pathophysiology
Also called tinea, it is an infectious mycosis of the skin, due to a fungal intrusion of the skin, hair, or nails. Common cases include hand-foot tinea, tinea corporis, tinea cruris, tinea unguium, tinea capitis and tinea versicolor. It has a high incidence rate in warm seasons and warm areas.
- Hand- foot tinea: The skin lesion is in most cases limited to the palm, sole, and between the toes. It causes itching, burning, and stinging sensations. The skin between the toes reddens, cracks open, and crumbles. In extreme long-lasting cases, the toenails may become infected, discolored, and overgrown. The fungus may spread to underside of foot, beneath the arch, producing groups of itching blisters and peeling of the skin.
- Nail tinea (onychomycosis): It results mainly from the spreading of hand-foot tinea. Its clinical manifestations include thick growth of the nail edge or the whole nail, with rough and uneven surface, loss of luster, opaqueness of the nail and the colour turning gray. The surrounding cuticle may become red, tender, and swollen, and ooze pus if a bacterial infection accompanies. It is also manifested by crispness of the affected nail, which is often incomplete or misshaped, but painless.
- Tinea corporis and Tinea cruris: Tinea on the face, neck, torso or limbs is classified as tinea corporis. Tinea cruris refers to those on the inside surface of the upper end of the thigh, including those, which spread to the genital organs or buttocks. It is manifested by ring- shaped or multi-ring-shaped erythemas with clear and prominent boundaries, papular eruptions, vesicles (lesion filled with clear fluid), scabs, which are mostly near the boundaries. The affected area may be extremely itchy.
- Tinea capitis: This is a kind of surface mycosis on the scalp and hair, found mainly among children. At first, there appear papular eruptions on the hair follicles. These are covered with grayish, or yellowish, or white scales. The scales may join together, or spread separately. The affected hair is dry and crisp, and gradually it begins scaling off unevenly. Later, the hair follicles become damaged, may result in permanent scars. The scalp itches and smells. The course is chronic.
Pathogenesis and pathophysiology
These are called shu jie (summer eruption) in the classics and are believed to be caused by invasion of pathogenic summerheat. They are often present as acute, suppurative infection of the hair follicles or the connective tissue of the hair follicles. Boils or skin abscesses are inflamed and pus-filled areas of skin that look like oversized pimples. A boil generally starts as a reddened, tender area that becomes firm and hard over time. Eventually, the centre of the boil softens and becomes filled with pus that finally forms a head and drains out through the skin. Also known as furuncles, boils are painful and can develop anywhere on the body, but often in areas like armpits, breasts, buttocks, face, genitals, and neck.
This condition is apt to occur around the head, face, neck, and hip. The boils may take the form of small, hard nodes at the onset and localized redness of skin, swelling heat, heat, and pain may all be present. Later on the nodes become soft and a whitish yellowish, suppurating pin-head sized lesion may appear at the top of the boil. Recovery will not occur until the boil is perforated and the pus discharged. Boils often leave scars after recovery. The adjacent lymph nodes are often found to be enlarged. In sever cases, systemic symptoms such as fever, are also present.
There are a number of different types of boils
Furuncle or carbuncle ?
This is an abscess that is caused by the Staphylococcus aureus bacteria and can have more than one opening. It may be accompanied by fever or chills. Cystic acne ?this type of abscess forms when the oil ducts in the skin become clogged, causing infection. This is commonly seen in adolescents. Hidradenitis suppurativa ?this is a condition where multiple abscesses form under the armpits or groin area and is generally caused by an inflammation of the sweat glands. Pilonidal cyst ?this is a specific type of abscess that develops in the crease of the buttocks often resulting from an ingrowing hair that continues to grow, or from long periods of sitting. This type of abscess needs to be removed surgically.
What are the symptoms of boils?
A red lump on the skin that grows and becomes filled with pus. Tenderness and pain, which is sometimes severe in the affected area. Fever, occasionally. Septicaemia can be a complication resulting from boils.
What causes boils? There are a number of causes of boils. One cause can be from an ingrown hair causing an infection of a hair follicle, usually by Staphylococcus bacteria. Others may be caused by a foreign object such as a splinter becoming stuck in the skin and causing an infection. Additional causes are blocked sweat glands that become infected or any break in the skin that allows bacteria to enter. The pus that collects in a boil also contains bacteria that are highly infectious.
Anyone may have a boil form, however, there are some people who are more susceptible, including people with diabetes and kidney problems. Also, if a person suffers from immune system deficiencies, they may be more susceptible to boils.
Dermatitis caused specifically by insect bites ‘Chong Yao Pi Yan’
Pathogenesis and pathophysiology: This condition is caused by toxins due to insect bites or stings by such insects as lice, mosquitoes, ticks, bees or centipedes. This category of disease is mostly caused by insect sting or contact with insects. These give rise to papules, vesicles, pustules, and erythema or wheals. This condition is characterized by its aggressive expansion or discharge of yellowish fluid. The itching sensation is extreme, as if a worm were crawling on one.
Diagnosis: Such conditions primarily occur on the exposed extremities and present as minor bleeding, papules, and wheals. Pustules may often be seen in the center of each spot. Itching and pain are variable. As for bites by insects with occult wings, they are characterized by linear of strip-like swelling upon which give rise to sensations of heat and pain.