7.2 Skin Diseases and Disorders
Key Takeaways
- Primary lesions such as macules, papules, vesicles, pustules, bullae, wheals, and tubercles occur on previously unbroken skin; secondary lesions such as scales, crusts, excoriations, fissures, ulcers, and scars develop as skin breaks down or heals
- Non-contagious skin disorders like contact dermatitis, eczema, psoriasis, acne vulgaris, rosacea, and milia are serviceable, usually with adjusted products or technique
- Herpes simplex, verruca (warts), tinea, and impetigo are contagious skin diseases that require refusing the service and referring the client to a physician
- The ABCDE rule (Asymmetry, Border, Color, Diameter, Evolving) helps flag a suspicious lesion for physician referral without requiring the cosmetologist to diagnose it
- Recognizing lesion type and contagion status, rather than memorizing every disease name in isolation, is the skill the PSI exam is actually testing
Skin Diseases and Disorders
Quick Answer: A skin lesion is any change in the structure of skin tissue. Primary lesions arise on previously unbroken skin, and secondary lesions develop as a primary lesion changes or heals. Skin conditions divide the same way hair and scalp conditions do: non-contagious disorders you may service, often with modification, and contagious or actively infectious diseases you must refuse and refer.
Primary Skin Lesions
Recognizing lesion types is a foundational skill tested throughout Domain 2. You will typically be given a description and asked to classify it correctly.
| Primary Lesion | Description | Example |
|---|---|---|
| Macule | Flat, discolored spot | Freckle |
| Papule | Small, raised, solid bump | Early pimple |
| Vesicle | Small, fluid-filled blister | Poison ivy reaction |
| Pustule | Raised bump containing pus | Acne pimple |
| Bulla | Large fluid-filled blister | Large blister or burn |
| Wheal | Itchy, swollen, raised bump | Insect bite, hives |
| Tubercle | Solid, abnormal, palpable lump below the skin, larger than a papule | Cyst prior to rupture |
Secondary Skin Lesions
| Secondary Lesion | Description | Example |
|---|---|---|
| Scale | Flaking accumulation of dead skin cells | Dandruff, psoriasis |
| Crust | Dried body fluid mixed with skin debris | Scab |
| Excoriation | Skin sore or abrasion from scratching or scraping | Scratched insect bite |
| Fissure | Crack in the skin that extends into the dermis | Chapped lips or hands |
| Ulcer | Open sore on skin or mucous membrane with loss of tissue | Cold sore ulcer |
| Cicatrix (scar) | Fibrous tissue that replaces normal tissue after injury | Healed cut |
Non-Contagious Skin Disorders: Proceed (Often with Modification)
| Disorder | Cause | Notes | Service Decision |
|---|---|---|---|
| Contact dermatitis | Irritant or allergic reaction to a substance | Redness, itching, sometimes blistering | Proceed once the trigger is identified or avoided; patch test new products |
| Eczema | Chronic inflammatory skin condition | Dry, itchy, inflamed patches | Proceed; avoid fragranced or irritating products |
| Psoriasis | Autoimmune overproduction of skin cells | Thick, silvery scaly plaques | Proceed if skin is intact; avoid irritating broken or cracked areas |
| Acne vulgaris | Clogged follicles, excess oil, bacteria | Comedones, papules, pustules | Proceed with mild to moderate cases; refer severe cystic acne for extractions or peels |
| Rosacea | Vascular disorder | Facial redness, visible blood vessels, sensitivity | Proceed with gentle products; avoid heat and aggressive extraction |
| Milia | Keratin trapped under the skin | Small, hard, white cysts | Proceed with routine services; lancing/extraction is outside a cosmetologist's scope |
| Hyperkeratosis / keratoma (callus) | Excess keratin buildup from friction or pressure | Thickened, hardened skin | Proceed; safely reduce buildup with appropriate implements |
Contagious Skin Diseases: Refuse and Refer
| Disease | Cause | Key Signs | Action |
|---|---|---|---|
| Herpes simplex (cold sore/fever blister) | Viral | Painful, fluid-filled blisters, often at the lip | Refuse service on or near the lesion; refer if active |
| Verruca (wart) | Viral (HPV) | Rough, raised, well-defined growth | Avoid direct contact or service on the lesion; refer for removal |
| Tinea (ringworm of the skin) | Fungal | Ring-shaped, red, scaly patch | Refuse service; refer to a physician |
| Impetigo | Bacterial | Honey-colored, crusted sores | Refuse service; refer to a physician |
Recognizing Suspicious Lesions: Refer, Never Diagnose
A cosmetologist never diagnoses skin cancer, but recognizing a suspicious lesion and referring the client to a physician is well within scope and is tested on the exam. The ABCDE rule flags lesions that need medical evaluation:
- Asymmetry — the two halves do not match
- Border — irregular, ragged, or blurred edges
- Color — uneven color or multiple colors within one lesion
- Diameter — larger than about 6mm, roughly the size of a pencil eraser
- Evolving — changing in size, shape, color, or symptoms over time
The three skin cancer types most relevant to a consultation are basal cell carcinoma (most common, slow-growing, often a pearly bump), squamous cell carcinoma (a scaly red patch or open sore that does not heal), and melanoma (the most dangerous, often an irregular mole matching ABCDE criteria). Your role in every case is the same: politely decline to service the immediate area, recommend the client see a dermatologist, and document the referral on the consultation card.
Decision Pattern to Remember
Just as with the scalp, non-contagious skin disorders such as dermatitis, eczema, psoriasis, acne, rosacea, and milia are serviceable; you simply adjust technique or products. Contagious skin diseases caused by a virus, fungus, or bacterium are not serviceable until treated. Any lesion matching ABCDE criteria is a referral, never a service decision you make yourself.
Documenting Skin Findings at Consultation
Every skin analysis begins before a single product touches the client: look at overall tone and texture, note any lesions and where they are located, and ask about known allergies, current medications (some increase sun sensitivity or thin the skin), and recent sun exposure or peels. Record what you observe and what you decide on the consultation card, using the same proceed, modify, or refer language covered in the hair and scalp section. This habit matters most on borderline calls, such as a client with widespread but mild acne who wants a facial, or dry, flaking patches that could be simple dehydration or early psoriasis; a documented, consistent decision process protects the client and the salon regardless of which condition turns out to be correct.
Which primary lesion is described as a large fluid-filled blister, larger than a vesicle?
A client has a scaly, ring-shaped, red patch of skin on the forearm. What is the correct action?
Which skin condition is generally safe to service with only product or technique modification, since it is non-contagious?
A mole has uneven coloring, a blurred border, and has grown noticeably larger over the past two months. Applying the ABCDE rule, what should you do?