Anhidrosis
Anhidrosis (or hypohidrosis when sweating is only partly reduced) is a condition in which the sweat glands lose, or largely lose, their ability to produce sweat in response to heat or physical exertion. It may affect just a few areas of skin or the whole body. Either way, it takes away the body's most important natural cooling mechanism and directly threatens its ability to regulate temperature.
The causes of anhidrosis fall into a few main groups:
- Nerve damage (neuropathic/neurogenic): The sympathetic nerve signals that control the sweat glands are interrupted. The damage may be central (stroke, spinal cord injury) or peripheral (diabetic neuropathy, Horner syndrome, autonomic ganglion disorders).
- Problems in the sweat glands themselves (dermatogenic/glandular): The eccrine sweat glands are structurally damaged, shrink away or have their outlets blocked. Causes include inherited conditions (such as hypohidrotic ectodermal dysplasia), chronic or autoimmune skin diseases (scleroderma, psoriasis, lichen sclerosus) and extensive skin injury (deep burns, fibrous scarring, miliaria profunda).
- Medications and whole-body factors (pharmacological/systemic): Side effects of drugs with anticholinergic properties (such as tricyclic antidepressants, antihistamines and antispasmodics) that block muscarinic receptors on the sweat glands, or severe dehydration and electrolyte imbalance.
At Haute-Derma, our approach to anhidrosis starts by working out whether the problem lies in the skin or in a wider systemic condition and by assessing how well you tolerate heat. From there we build a personalized plan to protect the skin barrier, help keep the sweat ducts open and prevent dangerous overheating.
Clinical Features and Differential Diagnosis
Examination focuses on local signs in the skin and on how the body responds to heat or exercise:
- Dry, hot skin: Affected skin stays dry, rough or smooth and shiny, with no dampness or beads of sweat even in hot weather or after hard exercise.
- Heat intolerance: When body temperature rises and the body cannot cool itself, symptoms come on quickly: flushing, dizziness, headache, nausea, muscle cramps, a racing heart and rapid breathing.
- Compensatory hyperhidrosis: When anhidrosis is patchy, the remaining healthy skin often sweats excessively to make up for the areas that no longer work.
- Associated skin changes: Depending on the underlying condition blocking the ducts, there may be scaling, deep heat-rash papules (miliaria profunda), skin thinning or fibrosis.
- Risk of acute complications: Generalized anhidrosis carries a high risk of heat exhaustion or life-threatening heatstroke if not managed promptly.
How Haute-Derma Diagnoses and Treats Anhidrosis
- Specialist assessment and sweat testing: Your doctor examines you and checks your sweat response using the starch-iodine test (Minor test) or heat stimulation. We also take a detailed history of your general health, skin problems and current medications.
- Finding and controlling the root cause: We determine whether the cause is nerve damage, blocked sweat ducts or a medication side effect. Your doctor then adjusts topical or oral treatment, stops anticholinergic drugs where possible and treats any underlying skin disease.
- Managing your environment and preventing heatstroke: We show you how to keep your surroundings cool, replace fluids and electrolytes promptly and avoid strenuous activity outdoors in the heat. This step is vital for preventing heat exhaustion and dangerous heatstroke.
- Restoring and protecting the skin barrier: We recommend a gentle skincare routine with light, non-comedogenic moisturizers that won't clog the follicles. This helps repair the skin barrier, keep the sweat duct openings clear and calm dry, irritated skin.
Common Types and Causes of Anhidrosis
| Type / Cause | Mechanism and Clinical Features |
|---|---|
| Neurogenic anhidrosis | Interrupted sympathetic signals (diabetes, spinal cord disease, Horner syndrome). Skin is completely dry in the area supplied by the affected nerves, but the glands themselves are structurally normal. |
| Anhidrosis from duct blockage or skin damage (dermatogenic) | Ducts blocked by miliaria profunda, burn scars, scleroderma or psoriasis. The sweat ducts are damaged or permanently destroyed. |
| Drug-induced anhidrosis (pharmacological) | Caused by anticholinergic drugs, antidepressants or antihistamines. Usually reversible once the drug is stopped. |
| Hypohidrotic ectodermal dysplasia | A rare inherited condition in which sweat glands are underdeveloped or absent from birth. Patients have very dry skin, sparse hair and malformed teeth. |
