Skin Disorders, Diseases, and Contraindications
Lesion vocabulary
Primary lesions include macule (flat color change), papule (small solid elevation), pustule (pus-filled), vesicle (small blister), bulla (large blister), wheal (edema, as in hives), nodule, tumor, and cyst. Secondary lesions include scale, crust, excoriation, fissure, ulcer, atrophy, and scar.
Conditions versus diseases
Estheticians treat conditions - comedones, dehydration, oiliness, mild texture - and refer diseases. Contagious and referral-worthy findings include herpes simplex (cold sores), verruca (warts), impetigo, tinea (fungal infections), conjunctivitis, and undiagnosed rashes. Acne, rosacea, melasma, vitiligo, eczema, and psoriasis are managed with medical care; you may support the skin but must not treat the disease. Use the ABCDE guide for moles (asymmetry, border, color, diameter, evolving) and refuse service, referring immediately.
Contraindications
Avoid waxing and chemical exfoliation over isotretinoin use, recent retinoid use, sunburn, freshly exfoliated or peeled skin, active infection, open lesions, or undiagnosed moles; check for diabetes, blood thinners, pregnancy, and photosensitivity because healing and sensitivity change.
Worked example: A client arrives with a red, tender, swollen area around the nostril and says it is "just a pimple." You do not extract it; you decline the service, explain the risk, and refer. Extracting a pustule in the triangle of the face is a classic wrong answer.