Disease Terminology

Definitions

• Acute Disease: Rapid onset with symptoms that appear and change quickly, and are intense and of short duration
• Allergy: Sensitized person develops an allergic reaction to harmless substances, with symptoms like pruritic rash, inflammation, hay fever, and anaphylactic shock, and signs aren't confined to the application area, lack clear boundaries, and don't subside after allergen removal
• Chronic Disease: Long-lasting, develops over time, worsens, and occurs in recurring episodes
• Congenital Disease: Passed on through direct contact
• Diagnosis: Recognizing a disease based on its symptoms
• Epidemic: Disease that attacks a large number of people simultaneously in a specific locality
• Erythematous: Skin and/or mucous membranes exhibit abnormal redness due to an inflammatory response
• Etiology/Aetiology: Study of the causes of diseases or conditions
• Eudermic: Substances that are skin-friendly and non-irritating
• Infectious Disease: Caused by pathogenic microorganisms that spread directly or indirectly
• Inflammation: Immune response with redness, pain, itching, swelling, and heat that can be acute or chronic, localized, or result from injury, irritation, or infection
• Occupational Disease: Caused by certain types of employment like dermatitis, hearing loss, and eye diseases
• Pandemic: New disease that spreads worldwide with little to no resistance
• Parasitic Disease: Caused by fungal or animal parasites
• Pathogenic Disease: Result from organisms that produce illness
• Pathology: Study of diseases and their effects
• Porphyria: Hereditary diseases affecting skin/nervous system due to abnormal hemoglobin metabolism, with extreme sunlight sensitivity and poor healing in porphyria cutanea tarda
• Prognosis: Predicting the probable course and duration of a disease
• Pruritic: Skin sensation that compels scratching
• Seasonal Disease: Influenced by weather changes throughout the year
• Skin Disease: Infection affecting the skin, often with objective signs
• Systemic Disease: Involves under- or over-functioning of internal glands and affects the entire body
• Trichology: Study of hair
• Venereal Disease: Contagious infections acquired through sexual relations with an infected person

Topography of the Skin

• Refers to the texture and components creating the unique surface of the skin in different areas
• Thickness varies (0.2 cm to 0.05 cm) based on function, being thickest on palms/soles and thinnest on eyelids/lips and is linked to protection and ability to manage mechanical stress
• Smoothness determines stretchability in specific areas, with the face being smoother and elbows having furrows for mobility
• Skin tension affects mobility, being firm/taut over bony structures and flaccid over joints, where ridges (hills) and sulci (valleys) create fingerprints, enhancing grip
• Elasticity enables adapting to body movements and changes in underlying structures, pigmentation protects and indicates systemic diseases
• The vascular network feeds the skin for cellular metabolism, and hair protects, manages temperature, and offers mechanical protection
• Scarring alters the skin's texture after trauma or infection

Wound Healing and Scarring

• Somatologists combine treatments for improvement, but complete scar erasure is unlikely
• The wound healing cascade has four phases controlled by growth factors (peptides)

Phases of Wound Healing

• Phase 1: Haemostasis: Blood vessels constrict to reduce bleeding, stimulated by platelets clumping to form a plug, blood clotting proteins release thrombin to form a fibrin clot, mast cells release histamine to increase cellular permeability, and growth factors promote coagulation
• Phase 2: Inflammation: Capillaries enlarge from growth factors, fluids accumulate with nutrients, oxygen, and WBCs, macrophages clean out debris via phagocytosis and produce growth factors, and a longer stage means a longer healing process
• Phase 3: Proliferation: New cells are created, fibroblasts are stimulated to produce collagen/elastin, fibroblasts synthesize collagen, matrix metalloproteinases (MMPs) remodel the extracellular matrix while breaking down old collagen, collagenase breaks down the peptide bonds in collagen, tissue inhibitors of metalloproteinases (TIMPs) inhibit collagenase, and ineffective TIMPs lead to excessive collagen breakdown
• Phase 4: Remodeling: Immature collagen (type 3) is replaced by mature collagen (type 1) What happens if proliferation doesn't end?: TIMPs fail to regulate MMPs, new collagen formation continues unchecked, leading to excessive tissue growth/hypertrophic scars and if collagen production is insufficient, an atrophic scar may develop
• Extended Inflammatory Phase: Chronic wound results, fibroblasts do not receive signals to produce new collagen due to continued WBC activity, TIMPs break down collagenases causing fibroblasts to produce more immature collagen, and without healthy collagen/new cells, the wound remains "open" and the healing process cannot continue

Scarring

• Epidermal wounds close through epidermal migration influenced by epidermal growth factor, while dermal wounds close through collagenesis via fibroblast stimulation, and complications arise from excessive or insufficient collagen production by fibroblasts
• Scarring is a natural outcome, but the type, depth, and size of a scar depend on the damaged regions, leading to dermal inflammation, altering skin topography, and loss of characteristics
• If collagenesis halts inappropriately by tissue inhibitors of metalloproteinases (TIMPs), an excess of immature may accumulate and form a surplus of tissue, causing a hypertrophic scar is then characterized by excessive collagen deposition and a decrease in collagenase activity
• An atrophic scar results from inadequate collagen production after cellular injury

Common Post-Acne Scars

• Ice Pick Scars:
  • Deep, narrow, and pitted appearance
  • Cause: Severe acne that penetrates deep into the skin, where it is difficult to treat and may need deep chemical peels, microneedling, or punch excision
• Boxcar Scars:
  • Broad, shallow-to-medium depressions with sharp edges
  • Cause: Inflammatory acne that destroys collagen
    • Treatments such as Microneedling, laser resurfacing, or dermal fillers can help
• Rolling Scars:
  • Wide, wave-like depressions with smooth edges
  • Cause: Damage beneath the skin surface, often due to long-term inflammation.
    • Subcision, microneedling, or laser treatments work well.

Acne Scar Prevention

• Scar prevention is better than treatment
• Manage inflammation promptly to minimize skin damage
• Avoid picking or popping lesions to prevent further irritation and scarring
• Use ingredients that promote healthy skin healing

Common Topical Treatments

• Topical Retinoids: Increase cell turnover, unclog pores, stimulate collagen production, and treat post-inflammatory hyperpigmentation as well as mild atrophic scars
• Silicone Gels/Sheets: Used for hypertrophic scars and keloids; They help flatten and soften raised scars while also reducing redness
• Chemical Peels: Exfoliate skin using acids to promote renewal

Benefits of Scar Treatments

• Fibroblast Stimulation: Promotes collagen production
• Glycosaminoglycans (GAGs) stimulation: Increases hydration/elasticity

Mechanical Resurfacing Techniques

• Dermabrasion: Medical-level, deeper mechanical exfoliation, often under anesthesia; ideal for severe scarring
• Microdermabrasion: Superficial treatment that removes the stratum corneum for maintenance purposes but not for deep scars

Laser and Radiofrequency Treatments

• Ablative Lasers (CO2, Er:YAG): Remove top layers, stimulate new collagen, resurface deeper scars, and involve longer downtime
• Non-Ablative Lasers: Work deeper without removing surface layers, stimulate collagen over time, and may need more sessions but less downtime

Lasers

• Fractional Laser: Creates micro-columns of damage surrounded by healthy skin and balances effectiveness with healing

Punch Techniques

• Can be used for deep ice pick or boxcar scars
• Punch Excision: Surgical removal and stitching
• Punch Elevation: Lift and level the bottom of the scar with surrounding skin using laser or RF tools

Surgical and Fill Options

• Subcision: Needle breaks fibrotic bands to pull down the scar which stimulates healing and collagen
• Dermal Grafting: Skin transplant from another area for deep/wide scars
• Tissue Augmentation: Fillers (hyaluronic acid, fat transplants) for smoother appearance with temporary (6-18 months) or semi-permanent results

Microneedling

• Tiny needles (0.5–2.5 mm) create micro-injuries to trigger collagen production that is safe for all skin types and has a lower risk of post-inflammatory hyperpigmentation (PIH)
• Treatment depth depends on scar type: 0.5 mm for pigmentation and 1.5-2.5 mm for deeper scars.
• Combination Therapy Example treatments include:
  • Microneedling + PRP (platelet-rich plasma)
  • TCA CROSS + Laser for stubborn scars

Acne Scar Recaps

• Strategies Classify scars as either:
  • Atrophic (Indented): Ice pick, rolling, or boxcar scars, best treated with collagen-stimulating techniques
  • Hypertrophic/Keloid (Raised) treated with silicone, steroid injections, or laser therapies

Types of Acne

• Acne Conglobata: Typically affects males due to oily skin/enlarged sebaceous glands, this contains nodules leading to scarring and usually appears in early puberty, common in those with fair skin, and typically on the back, buttocks, and thighs
• Post-Adolescent Facial Acne: Pyoderma Faciale: A severe form of acne in women aged 20-30, limited to the face, may indicate endocrine disorders, and is often preceded by emotional trauma and is associated with extreme facial oiliness
• Acne Tropicalis: Similar to acne conglobata (but more severe), is common in moist/humid conditions, occurs around age 25, affects the trunk, face, buttocks, thighs, neck, and arms, and treatment involves changing the climate.
• Acne Venenata: Contact acne caused by substances like pomade, manifests on the scalp, forehead, and temples that presents with pustules, inflammation, and congestion
• Acne Cosmetica: Similar to acne venenata but presents as congestion
• Acne Mechanica: Caused by mechanical stress and is located around the chin and collar
• Acne Neonatorum: Infant acne that appears two weeks after birth due to exposure to hormones that presents as discrete yellowish/whitish lesions, resolving by age five

Grades of Acne

• GRADE 1: No inflammation, some comedones
• GRADE 2: Some inflammation, papules, pustules
• GRADE 3: Inflammation, papules, pustules, scarring
• GRADE 4: Inflammation, pain, papules, pustules, cysts, severe scarring

Acne Look-a-Likes

• Peri-oral Dermatitis: Red rash around the mouth with scaly/flaky skin that is both itchy and may burn. Is more common for woman between 25 and 45 who use topical steroids or face creams
• Acne Rosacea: Red, pus-filled bumps on the face that commonly affects the middle-aged with fair skin that may react to a bacterium called bacillus oleronius causes the immune system to overreact

Acne Related Skin Conditions

• Folliculitis: It is an inflammatory disorder from ingrown hair due to hair removal, common in those with tight curly hair who are of African and Asian decent
• Keratosis Pilaris: Bumps caused when the skin produces too much of a protein, generally on the arms, thighs, cheeks, and buttocks which is white, sometimes red, and doesn't itch or hurt
• Sebaceous Hyperplasia: Small yellow bumps surrounded by hair is harmless and may be removed by cauterization
• Ingrown Hair: Infection of the hair that curves into the skin after waxing that causes tiny painful bumps more common with those with curly hair
• Basal Cell Carcinoma: Common on areas exposed to the sun where it appears as a transparent bump
• Plane Warts: Is caused by HPV that creates multiple flat papules on the face and hands
• Seborrheic Eczema (Seborrheic Dermatitis): Scaly patches and inflamed skin mainly on oily areas such as face, nose, ears and eyelids

Pigmentary Disorders

• Pigmentation disorders (dyschromias): Pathological changes resulting in hyper/hypopigmentation due to malfunctioning melanocytes in the epidermis

Hyperpigmentation vs Hypopigmentation

• Hyperpigmentation is characterized by darkened skin areas due to excessive melanin deposition
• Hypopigmentation (leukoderma): Decreased melanin
  • Hyperpigmentation: Skin patches darker than surrounding areas due to excess melanin or melanin being trapped

Hyperpigmentation Lesions & Disorders

• Tan: Temporary darkening from UV exposure as a natural response
• Ephelides (Freckles): Small, flat, light-brown spots on sun-exposed areas caused by genetic predisposition and sun exposure
• Stains (Dermal Pigmentation): Pigmented patches that don't fade over time, often from post-inflammatory pigmentation or injuries
• Lentigo (Liver Spots / Age Spots): Brown or black spots on aging/sun-exposed skin
• Melasma: Symmetrical brown patches on the face from hormonal changes, sun exposure, genetic factors which is more common in women and can be persistent
• Ochronosis: Bluish-black discoloration from long-term use of hydroquinone or certain skin-lightening products

Hypopigmentation Disorders

• Pityriasis Alba: Pale, scaly patches on the face of children/teens, thought to be related to eczema or dry skin
• Vitiligo: White patches from complete loss of pigment and caused by autoimmune destruction of melanocytes Albinism: Genetic condition causing little/no melanin production, affects skin, hair, and eye color, and people with albinism being very sun-sensitive

Types of Vitiligo

• Focal : A small isolated lesion in one specific area of the body
• Segmental - On one side of the body, spreads rapidly, then pauses and can remain unchanged for years Can develop into mixed vitiligo

Vitiligo Types

• NON-SEGMENTAL/GENERALISED
  • Various parts of the body
  • Acro-facial vitiligo
  • Vitiligo Vulgaris
  • Vitiligo universalis

Other Vitiligo

• Contact or occupational vitiligo