4.3 Scalp Disorders & Unfavourable Reactions

Key Takeaways

  • Common non-contagious scalp conditions include dandruff (pityriasis), seborrheic dermatitis, psoriasis, and dry scalp — services may proceed with adjusted products and care
  • Tinea capitis (ringworm) is a contagious fungal infection and pediculosis (head lice) is a contagious parasitic infestation — both require refusing service, referring the client, and sanitizing tools and workstation
  • Hairstylists must recognize and refer but must NOT diagnose or treat disease; that is medical scope of practice
  • Unfavourable reactions to chemical services include scalp irritation, allergic reaction, and over-processing — stop the service, rinse, and refer for medical care when severe
  • Alopecia has several types (androgenetic, areata, traction, postpartum); refer unexplained or sudden hair loss for medical evaluation rather than promising products will regrow hair
Last updated: August 2026

Recognizing Scalp Disorders & Unfavourable Reactions

Quick Answer: Hairstylists must recognize common scalp conditions — including dandruff, seborrheic dermatitis, psoriasis, ringworm (tinea capitis), and head lice (pediculosis) — but must not diagnose or treat disease. Contagious conditions require refusing service, referring the client to a physician, and sanitizing tools and workstation.

Scope of practice for a Red Seal hairstylist does not include medical diagnosis or treatment. Your responsibility is to recognize when something is wrong, decline or stop the service when needed, refer the client appropriately, and protect other clients through sanitation.

Common Non-Contagious Scalp Conditions

ConditionAppearanceLikely CauseStylist Action
Dry dandruff (pityriasis capitis)Fine, white, loose flakes on scalp and hairDry scalp, irritation from harsh productsService OK; use moisturizing/balancing shampoo; avoid hot water and scalp abrasion
Oily dandruff (pityriasis steatoides)Yellowish, greasy, sticky flakesExcess sebum mixing with skin cellsService OK; use clarifying/balancing shampoo; gentle scalp care
Seborrheic dermatitisGreasy yellow scales with inflamed, reddened skin, often along the hairlineChronic inflammatory condition related to yeast (Malassezia) on sebum-rich skinService OK with care; avoid irritating the scalp; recommend a medicated shampoo if appropriate; refer if severe
PsoriasisThick silvery scales over reddened plaques, often itchyChronic autoimmune skin conditionService OK with extreme care; do not pick or abrade scales; refer if widespread
Dry scalpTight feeling, powdery flakes, no inflammationLack of moisture, weather, harsh productsService OK; moisturizing scalp treatment

These are not contagious. You may perform services, but you should adjust products and technique to avoid worsening the condition and should recommend the client see a physician if symptoms are severe or persistent.

Contagious Conditions — Refuse Service and Refer

Some conditions are contagious and require you to stop or refuse the service, explain the situation tactfully to the client, recommend medical care, and sanitize your workstation and tools.

ConditionCauseSignsRequired Action
Tinea capitis (ringworm)Fungal infection of the scalp and hair shaftRound, scaly, reddish patches; broken hairs at the patch; sometimes kerion (inflamed mass); may include hair lossRefuse service; refer to physician; sanitize tools and station; do not apply any chemical or wet service
Pediculosis capitis (head lice)Parasitic infestation; adult lice and nits (eggs) attached to hair shaftIntense itching; nits (tiny white/gray oval eggs) firmly cemented to the hair shaft near the scalp, especially behind ears and at napeStop service immediately; tactfully inform client; refer for medical treatment; bag and launder all linens; sanitize all tools, capes, combs, brushes; do not resume service until cleared

A hairstylist must never apply color, perm, relaxer, or any wet service over active ringworm or lice — the chemicals can worsen the condition and the infestation will spread to other clients via shared tools and capes.

Alopecia (Hair Loss)

Alopecia is the general term for hair loss. Common types a stylist should recognize:

TypePatternLikely Cause
Androgenetic alopeciaThinning at crown and temples, receding hairlineGenetic and hormonal (pattern baldness)
Alopecia areataSmooth, round, sudden patches of complete hair lossAutoimmune; refer to physician
Traction alopeciaHair loss along hairline and at tight ponytail or braid attachment pointsRepeated tension from tight styles; reversible if style changes early
Postpartum / stress sheddingDiffuse thinning 2-4 months after a triggerTelogen effluvium; usually self-resolving

A stylist can advise on styling, gentle care, and avoiding traction, but unexplained or sudden hair loss must be referred for medical evaluation — do not promise products will regrow hair.

Unfavourable Reactions to Chemical Services

Even with proper analysis, a client may react adversely to a chemical service. Recognize and respond correctly:

ReactionSignsResponse
Scalp irritationBurning, redness, itching during or after a serviceStop service; rinse product immediately with cool water; apply soothing rinse; do not proceed
Allergic reactionHives, swelling (especially face/eyes), breathing difficulty, widespread rashStop service; rinse; call emergency services if severe; recommend urgent medical care; document
Over-processingHair breaking, gummy/stretching when wet, discolorationStop service; rinse; apply protein reconstructor only if hair can tolerate it; do not continue; recommend restorative care

A patch test (preliminary skin test) 24-48 hours before a color service is the standard protection against allergic reaction. Skipping it is unsafe practice and is a clear Red Seal exam topic.

Scope of Practice: Recognize, Refer, Do Not Treat

The hairstylist's scope is to:

  1. Recognize when a scalp or hair condition is abnormal or contagious
  2. Refuse or stop the service when contagious or when the scalp is broken, inflamed, or infected
  3. Refer the client to a physician for diagnosis and treatment
  4. Sanitize tools, capes, and workstation to protect other clients

You must not diagnose disease, prescribe medication, or apply products intended to treat disease. This boundary protects both you and the client.

Test Your Knowledge

A client presents with intense itching and tiny white oval nits firmly cemented to the hair shaft near the scalp, especially behind the ears. What is the correct action?

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B
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D
Test Your Knowledge

Which scalp condition is a contagious fungal infection that requires referral to a physician rather than a salon service?

A
B
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D