intradermmaal

In intradermal administration, the substance is injected into the dermis, the layer of skin just beneath the epidermis. The term intradermmaal is a common misspelling of intradermal, and it is helpful to recognize this variant as an error in formal writing.

Indications for intradermal injection include diagnostic testing and specific dermatologic or immunologic procedures. The most notable example is the tuberculin skin test (Mantoux test), which uses a small amount of purified protein derivative to elicit a delayed-type hypersensitivity reaction. Allergy testing with intradermal or prick methods, local anesthesia in dermatology, and certain immunotherapies may also employ this route.

Technique and administration involve delivering very small volumes, typically about 0.01 to 0.1 mL, with a fine-gauge needle (commonly 27- to 30-gauge) or a tuberculin syringe. The bevel is usually facing upward, the needle is inserted shallowly at about 5 to 15 degrees to the skin surface, and a characteristic wheal or bleb is produced to indicate proper placement within the dermal layer. Common sites include the inner forearm and the upper back.

Advantages of intradermal injection include localized action with minimal systemic absorption and the ability to monitor dermal reactions (as in skin tests). Limitations are the small available volume, potential for false-positive or false-negative results in tests, and the need for skilled technique to avoid subcutaneous delivery or skin injury. Safety considerations emphasize sterile technique, careful site selection, and avoidance in patients with skin infections at the injection area or certain dermatologic conditions.

See also: intramuscular injection, subcutaneous injection, tuberculin skin test.