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Acne Vulgaris
Acne vulgaris is a chronic inflammatory dermatosis which is notable for open and/or closed comedones (blackheads and whiteheads) and inflammatory lesions including papules, pustules or nodules.
Mild acne has <20 comedones or <15 inflammatory lesions or <30 total lesion count.
Moderate acne has 20-100 comedones or 15-20 inflammatory lesions or 30-125 total lesion count.
Severe papules/pustules or nodulocystic acne is the acne resistant to topical treatment or if scarring/nodular lesions are present.
Alopecia

Alopecia is an involuntary loss of hair usually in the scalp that may occur anywhere over the body.
Scarring alopecia is severe inflammation of the hair follicle result in irreversible damage.
Non-scarring alopecias are reversible.
Alopecia may  be abrupt or gradual in onset.
Most common causes include androgenic alopecia (male & female pattern baldness) & alopecia areata.
History should be reviewed for medications, severe diet restriction, vitamin A supplementation, thyroid symptoms, concomitant illness & stress factor.

Atopic Dermatitis
Atopic dermatitis or atopic eczema is chronic, relapsing, familial, symmetric and pruritic inflammatory skin disease that commonly presents during early infancy and childhood, but can persist or start in adulthood.
It is commonly associated w/ elevated serum immunoglobulin E levels and a personal or family history of allergies, allergic rhinitis and asthma.
It is one of the most common skin disease afflicting both children and adults.
Burns - Initial Management
Thermal burns are burns due to external heat sources that raises skin and tissue temperature causing tissue cell death or charring. Flame is the most common type of burn. Inhalation injury is found in 30% of victims of major flame burns.
Chemical burns are due to strong acids, alkalis, detergents or solvents coming into contact with the skin. Tissues are damaged by protein coagulation or liquefaction rather than hyperthermic activity.
Electrical burns are due to electrical current or lightning coming in contact with the body.
First degree burns or superficial burns appears similar to sunburn that is painful, dry, swollen, erythematous without blisters and involves only the epidermis.
Second degree burns or partial-thickness burns has appearance of moist blebs, formation of vesicle and blister; underlying tissue is mottled pink and white with good capillary refill; this involves the entire epidermis and a variable portion of the dermal layer.
Third degree burns or full-thickness burns appears dry, leathery eschar, mixed white waxy, khaki, mahogany and soot stained. It involves the entire epidermis and dermis, leaving no residual epidermis cells, may include fat, subcutaneous tissue, fascia, muscle and bone.
Candidiasis
Candida sp are the most common cause of fungal infections.
 It can cause infections that range from benign mucocutaneous illnesses to invasive process that may affect any organ.
 It is considered as normal flora in the gastrointestinal & genitourinary tracts, but when there is an imbalance in the ecological niche they can invade & cause disease.
Most common risk factors include: broad-spectrum antibiotics use, central venous catheters use, receipt of parenteral nutrition, receipt of renal placement therapy by patients in ICUs, neutropenia, implantable prosthetic devices use & receipt of immunosuppressive agents.
Cellulitis/Erysipelas
Cellulitis is a spreading bacterial skin infection that infects deeply involving the subcutaneous tissues.
It typically occurs in areas where the skin integrity has been compromised.
It may also result from blood-borne spread of infection to the skin and subcutaneous tissues.
It is commonly caused by beta-hemolytic streptococci and Staphylococcus aureus.
Erysipelas is a type of cellulitis with margins that are sharply demarcated, involves the epidermis and superficial lymphatics.
Onset of symptoms is acute whereas cellulitis has an indolent course.
It is more commonly caused by beta-hemolytic streptococci.
Contact Dermatitis

Contact dermatitis is an inflammation of the skin that can be acute or chronic that manifests as eczematous dermatitis due to exposure to substances in the environment.

Allergic contact dermatitis is an immunologic cell-mediated skin reaction to exposure to antigenic substances.
The lesions initially appear on the cutaneous site of principal exposure then may spread to other more distant sites due to contact or autosensitization. Lesions are typically asymmetrical and unilateral.
Specific signs and symptoms will depend on the duration, location, degree of sensitivity and concentration of allergens. The patch test shows reaction to allergen.
Irritant contact dermatitis is a non-immunologic skin reaction to skin irritants.
It is often localized to areas of thin skin eg eyelids, intertriginous areas.

Herpes Simplex Virus Infection
Primary herpes simplex virus (HSV) infection is first infection with either herpes simplex virus-1 (HSV-1) or herpes simplex virus-2 (HSV-2) in individuals who do not have antibodies to either HSV-1 or HSV-2.
First episode-non primary infection is infection with either HSV-1 or HSV-2 in individuals who have previously existing antibodies against HSV-1 or HSV-2 respectively.
Recurrent HSV infection results from reactivation of latent virus. It is usually brought about by triggering factors eg UV light, immunosuppression.
Orolabial HSV disease is mostly caused by HSV-1 that occurs most commonly in children <5 years of age. It is transmitted through close contact with individuals who have active viral shedding.
Genital HSV disease is caused by HSV-2 that is the usual cause of herpes genitalis. It typically occurs in adults and transmitted through sexual contact.
Impetigo & Ecthyma
Impetigo is a very contagious, superficial, bacterial skin infection that easily spreads among people in close contact.
Most cases occur in children and resolve spontaneously without scarring in approximately 14 days.
Ecthyma is a deeply ulcerated form of impetigo that extends to the dermis.
It has "punched-out" ulcers with yellow crust and elevated violaceous margins.
Most cases occur in children and elderly.
It may be a de novo infection or superinfection.
Melanoma
Melanoma is a skin neoplasm that originates from malignant transformation of melanocytes.
It commonly occurs in the extremities of women and on trunk or head and neck in men.
Metastases are via lymphatic and hematogenous routes.
Melasma
Melasma is an acquired hypermelanosis skin disorder that commonly affects women than men. It is characterized by irregular light to dark brown macules occurring in the sun-exposed areas of the face, neck and arms.
It occurs most commonly with pregnancy and with the use of contraceptive pills.
Other factors implicated in the etiopathogenesis are photosensitizing medications, mild ovarian or thyroid dysfunction and certain cosmetics.
Solar and ultraviolet exposure is the most common important factor in its development.
Molluscum Contagiosum
Molluscum contagiosum is an infection due to poxvirus that results into discrete skin lesions with central umbilication.
Spread is by skin-to-skin contact, fomites spread and autoinoculation.
Patients with atopic dermatitis, HIV or immunodeficiency are particularly susceptible.
Incubation period may be from 2-7 weeks.
In children, it usually presents with lesions on the face, scalp, ears, trunk and extremities and crural folds while in adults, it is typically sexually transmitted and affects the groin, genital area, thighs and lower abdomen.
Pityriasis (Tinea) Versicolor
Pityriasis (Tinea) versicolor is a fungal infection caused by Malassezia furfur. It is benign, superficial, and localized to the stratum corneum.
It may present as chronic or recurrent infection and may occur in healthy individuals.
It is more common in summer than winter months.
It presents with multiple well-demarcated macules or patches and finely scaled plaques with hypopigmentation or hyperpigmentation, hence the term "versicolor".
Lesions are usually found on the upper trunk, chest, back and shoulders, and may extend toward the neck, face and arms.
Psoriasis

Psoriasis is a systemic chronic skin disorder characterized by excessive keratinocytes proliferation that results into thickened scaly plaques, itching and inflammatory changes in the epidermis and dermis. It is transmitted genetically but can be provoked by environmental factors.
It is found in approximately 2% of the population that primarily affects the skin and joints.
It is associated with other inflammatory disorders and autoimmune diseases (eg psoriatic arthritis, inflammatory bowel disease, coronary artery disease).
Generally, it begins as red, scaling papules that coalesce to form round-to-oval plaques. The rashes are often pruritic and may be painful.

Rhytides (Wrinkles)
Rhytides or wrinkles are visible creases or folds in the skin.
Fine wrinkles is <1 mm in width while coarse wrinkles is >1 mm in width.
The decision to treat wrinkles depends on the degree that they bother the patient, the nature and severity of the wrinkles, and the patient's willingness to accept the risks and costs of treatment.
The patient should understand that protection from the sun at any age will reduce the risk of photoaging (including wrinkles), actinic keratoses and squamous cell cancer.
Rosacea
Rosacea is a chronic cutaneous disease of the convexities of the central face (cheeks, chin, nose and central forehead) w/ periorbital and perioral skin sparing. This condition is attributed to chronic vasodilation.
Remissions and exacerbations are common.
It typically appears after 30 years of age but may occur at any age.  It commonly affects fair-skinned individuals.
The common presenting symptoms are facial flushing, stinging/burning erythema, telangiectasia, edema, papules, pustules, ocular lesions, and hypertrophy of the sebaceous glands of the nose with fibrosis.
A history of episodic flushing often heralds onset of rosacea.
Scabies
Scabies is a contagious disease caused by the mite Sarcoptes scabiei var hominis.
The affected individual usually complains of having a highly pruritic rash that occurs at night.
It occurs more often in children <15 years of age, sexually active young adults, the immunocompromised and in persons living in crowded living conditions (eg nursing homes, military barracks).
Transmission is typically by direct skin contact with an infected person and in adults, sexual transmission is common.
Scleroderma
Scleroderma is a connective tissue disorder characterized by skin thickening and fibrosis. It is rare, autoimmune and chronic.
It has an idiopathic cause and not contagious.
Early microvascular damage, mononuclear cell infiltrates and slowly developing fibrosis are the important features of the tissue lesions.
The leading causes of death are pulmonary fibrosis and pulmonary arterial hypertension.
Seborrheic Dermatitis
Seborrheic dermatitis is a chronic inflammatory skin disorder characterized by fine scaling and erythema mostly confined to areas where sebaceous glands are prominent.
Pityrosporum ovale infection is common in seborrheic dermatitis.
The characteristic pattern is based on age group.
In infants it appears as cradle cap. It is a diffuse or focal scaling and crusting on the vertex of the scalp that sometimes accompanied by inflammation.
In young children, there is Tinea amiantacea which is one or several patches of dense, plate-like scales, 2-10 cm in size that appear anywhere on the scalp.
While adolescents have dandruff which are fine, dry, white, non-inflammatory scalp scaling with minor itching.
Tinea Capitis
Tinea capitis  is a contagious dermatophytosis affecting the hair shaft and follicles of the scalp, eyebrows and eyelashes.
It is most common in the crowded areas as infection originates from contact with a pet or an infected person and asymptomatic carriage persists indefinitely.
It primarily affects children 3-7 years of age.
The causative agents are the genus Trichophyton and Microsporum.
Cardinal clinical feature is the combination of inflammation with hair breakage and loss.
Tinea Corporis, Cruris & Pedis
Dermatophytoses are superficial fungal infections that have different presentations and are named based on location.
Tinea corporis (ringworm) usually presents with lesions of varying sizes, degree of inflammation and depth of involvement found on the trunk, extremities or face excluding the beard area in men.
Tinea cruris (jock itch) are lesions found on the groin. It may affect the proximal medial thighs and extend to the buttocks and abdomen. The scrotum and penis tend to be unaffected.
The red scaling lesions with raised borders have pustules and vesicles at the active edge of infected area.
Tinea pedis (athlete's foot) are lesions found in the interdigital spaces (most common), sole of foot, and sides of feet.
Tinea Unguium
Onychomycosis is a fungal infection of the nail bed, nail plate or both. It is caused by dermatophytes, non-dermatophyte molds and yeast.
Tinea unguium or dermatophytic onychomycosis is a dermatophyte infection of the nail more commonly affecting the toenails than the fingernails.
It is usually asymptomatic and patients first consult for cosmetic reasons.
It is suspected if there are changes in the 3rd or 5th toenail, involvement of the 1st and 5th toenails on the same foot and unilateral nail changes.
Urticaria
Urticaria is characterized by sudden appearance of wheals and/or angioedema.
The intensity of the pruritus varies but may be severe enough to disrupt sleep, work or school.
It is classified acute if the urticaria has been present for <6 weeks and chronic if >6 weeks. A specific cause is more likely to be identified in acute cases.
It can be triggered by immunological or nonimmunological mechanism.
Varicella-Zoster Virus Infection
Varicella, also known as chickenpox, is a self-limited benign disease caused by primary varicella-zoster virus (VZV) infection characterized by fever, malaise, and generalized pruritic vesicular rash.
The average incubation period is 14-16 days. It is transmitted via direct contact with vesicular fluid or inhalation of aerosolized respiratory secretions or via droplet route during face-to-face contact.
Hallmark sign is pruritic rash that begins in the scalp and face which eventually spreads to the trunks and extremities.
Vitiligo
Vitiligo is an acquired, often familial, melanocytopenic disorder that produces focal depigmentation of the skin.
About half of the patients has onset of lesion before the age of 20.
It is a progressive disease wherein spontaneous repigmentation may occur within 6 months.
Precipitating factors include emotional stress, sunburn, chemical exposure, skin trauma, inflammation, irritation or rash that may precede the lesions by 2-3 months.
Lesions are white-colored macules or patches with well-defined borders and otherwise normal skin surface.
Warts - Anogenital
Anogenital warts (condylomas) are caused by human papillomavirus (HPV) with >90% of the lesions caused by genotypes 6 & 11.
Patients who present with visible warts may also be infected with high-risk HPVs (eg types 16 & 18) which can cause subclinical lesions that are associated with intraepithelial neoplasia, cervical cancer and anogenital cancer.
Many HPV infections are subclinical, transient, and clear spontaneously within 12 months but may also remain latent and reactivate after several years.
Warts - Cutaneous
Cutaneous warts, also called verrucae, are benign proliferations of skin caused by human papillomavirus (HPV).
Most common warts on the hands and feet are due to HPV types 1, 2, 4, 27 & 57.
HPV is usually transmitted by contact with skin of an infected individual or by transmission of virus living in warm moist environment.
Autoinoculation may occur from traumatizing lesions by biting or scratching.
Incubation period is unknown but may range from months to years.